feat(viewport): line count getters (#283)

This reverts commit a4ed54327f.

.github/dependabot.yml

@@ -0,0 +1,22 @@
+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "daily"
+      time: "08:00"
+    labels:
+      - "dependencies"
+    commit-message:
+      prefix: "feat"
+      include: "scope"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+      time: "08:00"
+    labels:
+      - "dependencies"
+    commit-message:
+      prefix: "chore"
+      include: "scope"

.github/workflows/build.yml

@@ -11,12 +11,12 @@ jobs:
       GO111MODULE: "on"
     steps:
       - name: Install Go
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v3
         with:
           go-version: ${{ matrix.go-version }}
 
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Download Go modules
         run: go mod download

.github/workflows/coverage.yml

@@ -12,12 +12,12 @@ jobs:
       GO111MODULE: "on"
     steps:
       - name: Install Go
-        uses: actions/setup-go@v2
+        uses: actions/setup-go@v3
         with:
           go-version: ${{ matrix.go-version }}
 
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Coverage
         env:

.github/workflows/lint-soft.yml

@@ -0,0 +1,28 @@
+name: lint-soft
+on:
+  push:
+  pull_request:
+
+permissions:
+  contents: read
+  # Optional: allow read access to pull request. Use with `only-new-issues` option.
+  pull-requests: read
+
+jobs:
+  golangci:
+    name: lint-soft
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ^1
+
+      - uses: actions/checkout@v3
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          # Optional: golangci-lint command line arguments.
+          args: --config .golangci-soft.yml --issues-exit-code=0
+          # Optional: show only new issues if it's a pull request. The default value is `false`.
+          only-new-issues: true

.github/workflows/lint.yml

@@ -1,20 +1,28 @@
 name: lint
-on: [push, pull_request]
+on:
+  push:
+  pull_request:
+
+permissions:
+  contents: read
+  # Optional: allow read access to pull request. Use with `only-new-issues` option.
+  pull-requests: read
 
 jobs:
   golangci:
     name: lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: golangci-lint
-        uses: golangci/golangci-lint-action@v2
+      - name: Install Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ^1
+
+      - uses: actions/checkout@v3
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
         with:
-          # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
-          version: v1.30
           # Optional: golangci-lint command line arguments.
-          args: --issues-exit-code=0
-          # Optional: working directory, useful for monorepos
-          # working-directory: somedir
+          #args:
           # Optional: show only new issues if it's a pull request. The default value is `false`.
           only-new-issues: true

.github/workflows/soft-serve.yml

@@ -0,0 +1,12 @@
+name: soft-serve
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  soft-serve:
+    uses: charmbracelet/meta/.github/workflows/soft-serve.yml@main
+    secrets:
+      ssh-key: "${{ secrets.CHARM_SOFT_SERVE_KEY }}"

.golangci-soft.yml

@@ -0,0 +1,47 @@
+run:
+  tests: false
+
+issues:
+  include:
+    - EXC0001
+    - EXC0005
+    - EXC0011
+    - EXC0012
+    - EXC0013
+
+  max-issues-per-linter: 0
+  max-same-issues: 0
+
+linters:
+  enable:
+    # - dupl
+    - exhaustive
+    # - exhaustivestruct
+    - goconst
+    - godot
+    - godox
+    - gomnd
+    - gomoddirectives
+    - goprintffuncname
+    - ifshort
+    # - lll
+    - misspell
+    - nakedret
+    - nestif
+    - noctx
+    - nolintlint
+    - prealloc
+    - wrapcheck
+
+  # disable default linters, they are already enabled in .golangci.yml
+  disable:
+    - deadcode
+    - errcheck
+    - gosimple
+    - govet
+    - ineffassign
+    - staticcheck
+    - structcheck
+    - typecheck
+    - unused
+    - varcheck

.golangci.yml

@@ -2,26 +2,28 @@ run:
   tests: false
 
 issues:
+  include:
+    - EXC0001
+    - EXC0005
+    - EXC0011
+    - EXC0012
+    - EXC0013
+
   max-issues-per-linter: 0
   max-same-issues: 0
 
 linters:
   enable:
     - bodyclose
-    - dupl
     - exportloopref
-    - goconst
-    - godot
-    - godox
     - goimports
-    - golint
-    - gomnd
-    - goprintffuncname
     - gosec
-    - misspell
-    - prealloc
+    - nilerr
+    - predeclared
+    - revive
     - rowserrcheck
     - sqlclosecheck
+    - tparallel
     - unconvert
     - unparam
     - whitespace

README.md

@@ -8,14 +8,15 @@ Bubbles
 [![Latest Release](https://img.shields.io/github/release/charmbracelet/bubbles.svg)](https://github.com/charmbracelet/bubbles/releases)
 [![GoDoc](https://godoc.org/github.com/golang/gddo?status.svg)](https://pkg.go.dev/github.com/charmbracelet/bubbles)
 [![Build Status](https://github.com/charmbracelet/bubbles/workflows/build/badge.svg)](https://github.com/charmbracelet/bubbles/actions)
-[![Go ReportCard](http://goreportcard.com/badge/charmbracelet/bubbles)](http://goreportcard.com/report/charmbracelet/bubbles)
+[![Go ReportCard](https://goreportcard.com/badge/charmbracelet/bubbles)](https://goreportcard.com/report/charmbracelet/bubbles)
 
-Some components for [Bubble Tea](https://github.com/charmbracelet/bubbletea) applications.
-
-These components are used in production in [Glow][glow] and [Charm][charm].
+Some components for [Bubble Tea](https://github.com/charmbracelet/bubbletea)
+applications. These components are used in production in [Glow][glow],
+[Charm][charm] and [many other applications][otherstuff].
 
 [glow]: https://github.com/charmbracelet/glow
 [charm]: https://github.com/charmbracelet/charm
+[otherstuff]: https://github.com/charmbracelet/bubbletea/#bubble-tea-in-the-wild
 
 
 ## Spinner
@@ -25,7 +26,8 @@ These components are used in production in [Glow][glow] and [Charm][charm].
 A spinner, useful for indicating that some kind an operation is happening.
 There are a couple default ones, but you can also pass your own ”frames.”
 
-* [Example code](https://github.com/charmbracelet/tea/tree/master/examples/spinner/main.go)
+* [Example code, basic spinner](https://github.com/charmbracelet/bubbletea/tree/master/examples/spinner/main.go)
+* [Example code, various spinners](https://github.com/charmbracelet/bubbletea/tree/master/examples/spinners/main.go)
 
 
 ## Text Input
@@ -36,19 +38,43 @@ A text input field, akin to an `<input type="text">` in HTML. Supports unicode,
 pasting, in-place scrolling when the value exceeds the width of the element and
 the common, and many customization options.
 
-* [Example code, one field](https://github.com/charmbracelet/tea/tree/master/examples/textinput/main.go)
-* [Example code, many fields](https://github.com/charmbracelet/tea/tree/master/examples/textinputs/main.go)
+* [Example code, one field](https://github.com/charmbracelet/bubbletea/tree/master/examples/textinput/main.go)
+* [Example code, many fields](https://github.com/charmbracelet/bubbletea/tree/master/examples/textinputs/main.go)
 
+## Text Area
+
+<img src="https://stuff.charm.sh/bubbles-examples/textarea.gif" width="400" alt="Text Area Example">
+
+A text area field, akin to an `<textarea />` in HTML. Allows for input that
+spans multiple lines. Supports unicode, pasting, vertical scrolling when the
+value exceeds the width and height of the element,  and many customization
+options.
+
+* [Example code, chat input](https://github.com/charmbracelet/bubbletea/tree/master/examples/chat/main.go)
+* [Example code, story time input](https://github.com/charmbracelet/bubbletea/tree/master/examples/textarea/main.go)
+
+## Table
+
+<img src="https://stuff.charm.sh/bubbles-examples/table.gif" width="400" alt="Table Example">
+
+A component for displaying and navigating tabular data (columns and rows).
+Supports vertical scrolling and many customization options.
+
+* [Example code, countries and populations](https://github.com/charmbracelet/bubbletea/tree/master/examples/table/main.go)
 
 ## Progress
 
 <img src="https://stuff.charm.sh/bubbles-examples/progress.gif" width="800" alt="Progressbar Example">
 
-A simple, customizable progress meter. Supports solid and gradient fills. The
-empty and filled runes can be set to whatever you'd like. The percentage readout
-is customizable and can also be omitted entirely.
+A simple, customizable progress meter, with optional animation via
+[Harmonica][harmonica]. Supports solid and gradient fills. The empty and filled
+runes can be set to whatever you'd like. The percentage readout is customizable
+and can also be omitted entirely.
 
-* [Example code](https://github.com/charmbracelet/bubbletea/blob/master/examples/progress/main.go)
+* [Animated example](https://github.com/charmbracelet/bubbletea/blob/master/examples/progress-animated/main.go)
+* [Static example](https://github.com/charmbracelet/bubbletea/blob/master/examples/progress-static/main.go)
+
+[harmonica]: https://github.com/charmbracelet/harmonica
 
 
 ## Paginator
@@ -60,8 +86,7 @@ Supports "dot-style" pagination (similar to what you might see on iOS) and
 numeric page numbering, but you could also just use this component for the
 logic and visualize pagination however you like.
 
-This component is used in [Glow][glow] to browse documents and [Charm][charm] to
-browse SSH keys.
+* [Example code](https://github.com/charmbracelet/bubbletea/blob/master/examples/paginator/main.go)
 
 
 ## Viewport
@@ -72,23 +97,142 @@ A viewport for vertically scrolling content. Optionally includes standard
 pager keybindings and mouse wheel support. A high performance mode is available
 for applications which make use of the alternate screen buffer.
 
-* [Example code](https://github.com/charmbracelet/tea/tree/master/examples/pager/main.go)
+* [Example code](https://github.com/charmbracelet/bubbletea/tree/master/examples/pager/main.go)
 
-This component is well complimented with [Reflow][reflow] for ANSI-aware
+This component is well complemented with [Reflow][reflow] for ANSI-aware
 indenting and text wrapping.
 
 [reflow]: https://github.com/muesli/reflow
 
 
+## List
+
+<img src="https://stuff.charm.sh/bubbles-examples/list.gif" width="600" alt="List Example">
+
+A customizable, batteries-included component for browsing a set of items.
+Features pagination, fuzzy filtering, auto-generated help, an activity spinner,
+and status messages, all of which can be enabled and disabled as needed.
+Extrapolated from [Glow][glow].
+
+* [Example code, default list](https://github.com/charmbracelet/bubbletea/tree/master/examples/list-default/main.go)
+* [Example code, simple list](https://github.com/charmbracelet/bubbletea/tree/master/examples/list-simple/main.go)
+* [Example code, all features](https://github.com/charmbracelet/bubbletea/tree/master/examples/list-fancy/main.go)
+
+
+## Timer
+
+A simple, flexible component for counting down. The update frequency and output
+can be customized as you like.
+
+<img src="https://stuff.charm.sh/bubbles-examples/timer.gif" width="400" alt="Timer example">
+
+* [Example code](https://github.com/charmbracelet/bubbletea/blob/master/examples/timer/main.go)
+
+
+## Stopwatch
+
+<img src="https://stuff.charm.sh/bubbles-examples/stopwatch.gif" width="400" alt="Stopwatch example">
+
+A simple, flexible component for counting up. The update frequency and output
+can be customized as you see fit.
+
+* [Example code](https://github.com/charmbracelet/bubbletea/blob/master/examples/stopwatch/main.go)
+
+
+## Help
+
+<img src="https://stuff.charm.sh/bubbles-examples/help.gif" width="500" alt="Help Example">
+
+A customizable horizontal mini help view that automatically generates itself
+from your keybindings. It features single and multi-line modes, which the user
+can optionally toggle between. It will truncate gracefully if the terminal is
+too wide for the content.
+
+* [Example code](https://github.com/charmbracelet/bubbletea/blob/master/examples/help/main.go)
+
+
+## Key
+
+A non-visual component for managing keybindings. It’s useful for allowing users
+to remap keybindings as well as generating help views corresponding to your
+keybindings.
+
+```go
+type KeyMap struct {
+    Up key.Binding
+    Down key.Binding
+}
+
+var DefaultKeyMap = KeyMap{
+    Up: key.NewBinding(
+        key.WithKeys("k", "up"),        // actual keybindings
+        key.WithHelp("↑/k", "move up"), // corresponding help text
+    ),
+    Down: key.NewBinding(
+        key.WithKeys("j", "down"),
+        key.WithHelp("↓/j", "move down"),
+    ),
+}
+
+func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+    switch msg := msg.(type) {
+    case tea.KeyMsg:
+        switch {
+        case key.Matches(msg, DefaultKeyMap.Up):
+            // The user pressed up
+        case key.Matches(msg, DefaultKeyMap.Down):
+            // The user pressed down
+        }
+    }
+    return m, nil
+}
+```
+
+
+## Additional Bubbles
+
+<!-- in alphabetical order by author -->
+
+* [76creates/stickers](https://github.com/76creates/stickers): Responsive
+  flexbox and table components.
+* [calyptia/go-bubble-table](https://github.com/calyptia/go-bubble-table): An
+  interactive, customizable, scrollable table component.
+* [erikgeiser/promptkit](https://github.com/erikgeiser/promptkit): A collection
+  of common prompts for cases like selection, text input, and confirmation.
+  Each prompt comes with sensible defaults, remappable keybindings, any many
+  customization options.
+* [evertras/bubble-table](https://github.com/Evertras/bubble-table): Interactive,
+  customizable, paginated tables.
+* [knipferrc/teacup](https://github.com/knipferrc/teacup): Various handy
+  bubbles and utilities for building Bubble Tea applications.
+* [mritd/bubbles](https://github.com/mritd/bubbles): Some general-purpose
+  bubbles. Inputs with validation, menu selection, a modified progressbar, and
+  so on.
+* [treilik/bubbleboxer](https://github.com/treilik/bubbleboxer): Layout
+  multiple bubbles side-by-side in a layout-tree.
+* [treilik/bubblelister](https://github.com/treilik/bubblelister): An alternate
+  list that is scrollable without pagination and has the ability to contain
+  other bubbles as list items.
+
+If you’ve built a Bubble you think should be listed here,
+[let us know](mailto:vt100@charm.sh).
+
+## Feedback
+
+We’d love to hear your thoughts on this project. Feel free to drop us a note!
+
+* [Twitter](https://twitter.com/charmcli)
+* [The Fediverse](https://mastodon.social/@charmcli)
+* [Discord](https://charm.sh/chat)
+
 ## License
 
-[MIT](https://github.com/charmbracelet/teaparty/raw/master/LICENSE)
-
+[MIT](https://github.com/charmbracelet/bubbletea/raw/master/LICENSE)
 
 ***
 
 Part of [Charm](https://charm.sh).
 
-<a href="https://charm.sh/"><img alt="The Charm logo" src="https://stuff.charm.sh/charm-badge-unrounded.jpg" width="400"></a>
+<a href="https://charm.sh/"><img alt="The Charm logo" src="https://stuff.charm.sh/charm-badge.jpg" width="400"></a>
 
-Charm热爱开源! / Charm loves open source!
+Charm热爱开源 • Charm loves open source

cursor/cursor.go

@@ -0,0 +1,207 @@
+package cursor
+
+import (
+	"context"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+const defaultBlinkSpeed = time.Millisecond * 530
+
+// initialBlinkMsg initializes cursor blinking.
+type initialBlinkMsg struct{}
+
+// BlinkMsg signals that the cursor should blink. It contains metadata that
+// allows us to tell if the blink message is the one we're expecting.
+type BlinkMsg struct {
+	id  int
+	tag int
+}
+
+// blinkCanceled is sent when a blink operation is canceled.
+type blinkCanceled struct{}
+
+// blinkCtx manages cursor blinking.
+type blinkCtx struct {
+	ctx    context.Context
+	cancel context.CancelFunc
+}
+
+// Mode describes the behavior of the cursor.
+type Mode int
+
+// Available cursor modes.
+const (
+	CursorBlink Mode = iota
+	CursorStatic
+	CursorHide
+)
+
+// String returns the cursor mode in a human-readable format. This method is
+// provisional and for informational purposes only.
+func (c Mode) String() string {
+	return [...]string{
+		"blink",
+		"static",
+		"hidden",
+	}[c]
+}
+
+// Model is the Bubble Tea model for this cursor element.
+type Model struct {
+	BlinkSpeed time.Duration
+	// Style for styling the cursor block.
+	Style lipgloss.Style
+	// TextStyle is the style used for the cursor when it is hidden (when blinking).
+	// I.e. displaying normal text.
+	TextStyle lipgloss.Style
+
+	// char is the character under the cursor
+	char string
+	// The ID of this Model as it relates to other cursors
+	id int
+	// focus indicates whether the containing input is focused
+	focus bool
+	// Cursor Blink state.
+	Blink bool
+	// Used to manage cursor blink
+	blinkCtx *blinkCtx
+	// The ID of the blink message we're expecting to receive.
+	blinkTag int
+	// mode determines the behavior of the cursor
+	mode Mode
+}
+
+// New creates a new model with default settings.
+func New() Model {
+	return Model{
+		BlinkSpeed: defaultBlinkSpeed,
+
+		Blink: true,
+		mode:  CursorBlink,
+
+		blinkCtx: &blinkCtx{
+			ctx: context.Background(),
+		},
+	}
+}
+
+// Update updates the cursor.
+func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case initialBlinkMsg:
+		// We accept all initialBlinkMsgs generated by the Blink command.
+
+		if m.mode != CursorBlink || !m.focus {
+			return m, nil
+		}
+
+		cmd := m.BlinkCmd()
+		return m, cmd
+
+	case BlinkMsg:
+		// We're choosy about whether to accept blinkMsgs so that our cursor
+		// only exactly when it should.
+
+		// Is this model blink-able?
+		if m.mode != CursorBlink || !m.focus {
+			return m, nil
+		}
+
+		// Were we expecting this blink message?
+		if msg.id != m.id || msg.tag != m.blinkTag {
+			return m, nil
+		}
+
+		var cmd tea.Cmd
+		if m.mode == CursorBlink {
+			m.Blink = !m.Blink
+			cmd = m.BlinkCmd()
+		}
+		return m, cmd
+
+	case blinkCanceled: // no-op
+		return m, nil
+	}
+	return m, nil
+}
+
+// Mode returns the model's cursor mode. For available cursor modes, see
+// type Mode.
+func (m Model) Mode() Mode {
+	return m.mode
+}
+
+// SetMode sets the model's cursor mode. This method returns a command.
+//
+// For available cursor modes, see type CursorMode.
+func (m *Model) SetMode(mode Mode) tea.Cmd {
+	m.mode = mode
+	m.Blink = m.mode == CursorHide || !m.focus
+	if mode == CursorBlink {
+		return Blink
+	}
+	return nil
+}
+
+// BlinkCmd is an command used to manage cursor blinking.
+func (m *Model) BlinkCmd() tea.Cmd {
+	if m.mode != CursorBlink {
+		return nil
+	}
+
+	if m.blinkCtx != nil && m.blinkCtx.cancel != nil {
+		m.blinkCtx.cancel()
+	}
+
+	ctx, cancel := context.WithTimeout(m.blinkCtx.ctx, m.BlinkSpeed)
+	m.blinkCtx.cancel = cancel
+
+	m.blinkTag++
+
+	return func() tea.Msg {
+		defer cancel()
+		<-ctx.Done()
+		if ctx.Err() == context.DeadlineExceeded {
+			return BlinkMsg{id: m.id, tag: m.blinkTag}
+		}
+		return blinkCanceled{}
+	}
+}
+
+// Blink is a command used to initialize cursor blinking.
+func Blink() tea.Msg {
+	return initialBlinkMsg{}
+}
+
+// Focus focuses the cursor to allow it to blink if desired.
+func (m *Model) Focus() tea.Cmd {
+	m.focus = true
+	m.Blink = m.mode == CursorHide // show the cursor unless we've explicitly hidden it
+
+	if m.mode == CursorBlink && m.focus {
+		return m.BlinkCmd()
+	}
+	return nil
+}
+
+// Blur blurs the cursor.
+func (m *Model) Blur() {
+	m.focus = false
+	m.Blink = true
+}
+
+// SetChar sets the character under the cursor.
+func (m *Model) SetChar(char string) {
+	m.char = char
+}
+
+// View displays the cursor.
+func (m Model) View() string {
+	if m.Blink {
+		return m.TextStyle.Inline(true).Render(m.char)
+	}
+	return m.Style.Inline(true).Reverse(true).Render(m.char)
+}

go.mod

@@ -3,12 +3,14 @@ module github.com/charmbracelet/bubbles
 go 1.13
 
 require (
-	github.com/atotto/clipboard v0.1.2
-	github.com/charmbracelet/bubbletea v0.13.1
-	github.com/charmbracelet/lipgloss v0.1.2
+	github.com/atotto/clipboard v0.1.4
+	github.com/charmbracelet/bubbletea v0.22.1
+	github.com/charmbracelet/harmonica v0.2.0
+	github.com/charmbracelet/lipgloss v0.6.0
+	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0
-	github.com/mattn/go-runewidth v0.0.12
-	github.com/muesli/reflow v0.2.1-0.20210115123740-9e1d0d53df68
-	github.com/muesli/termenv v0.8.1
-	golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897 // indirect
+	github.com/mattn/go-runewidth v0.0.14
+	github.com/muesli/reflow v0.3.0
+	github.com/muesli/termenv v0.11.1-0.20220212125758-44cd13922739
+	github.com/sahilm/fuzzy v0.1.0
 )

go.sum

@@ -1,41 +1,50 @@
-github.com/atotto/clipboard v0.1.2 h1:YZCtFu5Ie8qX2VmVTBnrqLSiU9XOWwqNRmdT3gIQzbY=
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help/help.go

@@ -0,0 +1,233 @@
+package help
+
+import (
+	"strings"
+
+	"github.com/charmbracelet/bubbles/key"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+// KeyMap is a map of keybindings used to generate help. Since it's an
+// interface it can be any type, though struct or a map[string][]key.Binding
+// are likely candidates.
+//
+// Note that if a key is disabled (via key.Binding.SetEnabled) it will not be
+// rendered in the help view, so in theory generated help should self-manage.
+type KeyMap interface {
+
+	// ShortHelp returns a slice of bindings to be displayed in the short
+	// version of the help. The help bubble will render help in the order in
+	// which the help items are returned here.
+	ShortHelp() []key.Binding
+
+	// MoreHelp returns an extended group of help items, grouped by columns.
+	// The help bubble will render the help in the order in which the help
+	// items are returned here.
+	FullHelp() [][]key.Binding
+}
+
+// Styles is a set of available style definitions for the Help bubble.
+type Styles struct {
+	Ellipsis lipgloss.Style
+
+	// Styling for the short help
+	ShortKey       lipgloss.Style
+	ShortDesc      lipgloss.Style
+	ShortSeparator lipgloss.Style
+
+	// Styling for the full help
+	FullKey       lipgloss.Style
+	FullDesc      lipgloss.Style
+	FullSeparator lipgloss.Style
+}
+
+// Model contains the state of the help view.
+type Model struct {
+	Width   int
+	ShowAll bool // if true, render the "full" help menu
+
+	ShortSeparator string
+	FullSeparator  string
+
+	// The symbol we use in the short help when help items have been truncated
+	// due to width. Periods of ellipsis by default.
+	Ellipsis string
+
+	Styles Styles
+}
+
+// New creates a new help view with some useful defaults.
+func New() Model {
+	keyStyle := lipgloss.NewStyle().Foreground(lipgloss.AdaptiveColor{
+		Light: "#909090",
+		Dark:  "#626262",
+	})
+
+	descStyle := lipgloss.NewStyle().Foreground(lipgloss.AdaptiveColor{
+		Light: "#B2B2B2",
+		Dark:  "#4A4A4A",
+	})
+
+	sepStyle := lipgloss.NewStyle().Foreground(lipgloss.AdaptiveColor{
+		Light: "#DDDADA",
+		Dark:  "#3C3C3C",
+	})
+
+	return Model{
+		ShortSeparator: " • ",
+		FullSeparator:  "    ",
+		Ellipsis:       "…",
+		Styles: Styles{
+			ShortKey:       keyStyle,
+			ShortDesc:      descStyle,
+			ShortSeparator: sepStyle,
+			Ellipsis:       sepStyle.Copy(),
+			FullKey:        keyStyle.Copy(),
+			FullDesc:       descStyle.Copy(),
+			FullSeparator:  sepStyle.Copy(),
+		},
+	}
+}
+
+// NewModel creates a new help view with some useful defaults.
+//
+// Deprecated. Use New instead.
+var NewModel = New
+
+// Update helps satisfy the Bubble Tea Model interface. It's a no-op.
+func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
+	return m, nil
+}
+
+// View renders the help view's current state.
+func (m Model) View(k KeyMap) string {
+	if m.ShowAll {
+		return m.FullHelpView(k.FullHelp())
+	}
+	return m.ShortHelpView(k.ShortHelp())
+}
+
+// ShortHelpView renders a single line help view from a slice of keybindings.
+// If the line is longer than the maximum width it will be gracefully
+// truncated, showing only as many help items as possible.
+func (m Model) ShortHelpView(bindings []key.Binding) string {
+	if len(bindings) == 0 {
+		return ""
+	}
+
+	var b strings.Builder
+	var totalWidth int
+	var separator = m.Styles.ShortSeparator.Inline(true).Render(m.ShortSeparator)
+
+	for i, kb := range bindings {
+		if !kb.Enabled() {
+			continue
+		}
+
+		var sep string
+		if totalWidth > 0 && i < len(bindings) {
+			sep = separator
+		}
+
+		str := sep +
+			m.Styles.ShortKey.Inline(true).Render(kb.Help().Key) + " " +
+			m.Styles.ShortDesc.Inline(true).Render(kb.Help().Desc)
+
+		w := lipgloss.Width(str)
+
+		// If adding this help item would go over the available width, stop
+		// drawing.
+		if m.Width > 0 && totalWidth+w > m.Width {
+			// Although if there's room for an ellipsis, print that.
+			tail := " " + m.Styles.Ellipsis.Inline(true).Render(m.Ellipsis)
+			tailWidth := lipgloss.Width(tail)
+
+			if totalWidth+tailWidth < m.Width {
+				b.WriteString(tail)
+			}
+
+			break
+		}
+
+		totalWidth += w
+		b.WriteString(str)
+	}
+
+	return b.String()
+}
+
+// FullHelpView renders help columns from a slice of key binding slices. Each
+// top level slice entry renders into a column.
+func (m Model) FullHelpView(groups [][]key.Binding) string {
+	if len(groups) == 0 {
+		return ""
+	}
+
+	// Linter note: at this time we don't think it's worth the additional
+	// code complexity involved in preallocating this slice.
+	//nolint:prealloc
+	var (
+		out []string
+
+		totalWidth int
+		sep        = m.Styles.FullSeparator.Render(m.FullSeparator)
+		sepWidth   = lipgloss.Width(sep)
+	)
+
+	// Iterate over groups to build columns
+	for i, group := range groups {
+		if group == nil || !shouldRenderColumn(group) {
+			continue
+		}
+
+		var (
+			keys         []string
+			descriptions []string
+		)
+
+		// Separate keys and descriptions into different slices
+		for _, kb := range group {
+			if !kb.Enabled() {
+				continue
+			}
+			keys = append(keys, kb.Help().Key)
+			descriptions = append(descriptions, kb.Help().Desc)
+		}
+
+		col := lipgloss.JoinHorizontal(lipgloss.Top,
+			m.Styles.FullKey.Render(strings.Join(keys, "\n")),
+			m.Styles.FullKey.Render(" "),
+			m.Styles.FullDesc.Render(strings.Join(descriptions, "\n")),
+		)
+
+		// Column
+		totalWidth += lipgloss.Width(col)
+		if m.Width > 0 && totalWidth > m.Width {
+			break
+		}
+
+		out = append(out, col)
+
+		// Separator
+		if i < len(group)-1 {
+			totalWidth += sepWidth
+			if m.Width > 0 && totalWidth > m.Width {
+				break
+			}
+		}
+
+		out = append(out, sep)
+	}
+
+	return lipgloss.JoinHorizontal(lipgloss.Top, out...)
+}
+
+func shouldRenderColumn(b []key.Binding) (ok bool) {
+	for _, v := range b {
+		if v.Enabled() {
+			return true
+		}
+	}
+	return false
+}

key/key.go

@@ -0,0 +1,142 @@
+// Package key provides some types and functions for generating user-definable
+// keymappings useful in Bubble Tea components. There are a few different ways
+// you can define a keymapping with this package. Here's one example:
+//
+//	type KeyMap struct {
+//	    Up key.Binding
+//	    Down key.Binding
+//	}
+//
+//	var DefaultKeyMap = KeyMap{
+//	    Up: key.NewBinding(
+//	        key.WithKeys("k", "up"),        // actual keybindings
+//	        key.WithHelp("↑/k", "move up"), // corresponding help text
+//	    ),
+//	    Down: key.NewBinding(
+//	        key.WithKeys("j", "down"),
+//	        key.WithHelp("↓/j", "move down"),
+//	    ),
+//	}
+//
+//	func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+//	    switch msg := msg.(type) {
+//	    case tea.KeyMsg:
+//	        switch {
+//	        case key.Matches(msg, DefaultKeyMap.Up):
+//	            // The user pressed up
+//	        case key.Matches(msg, DefaultKeyMap.Down):
+//	            // The user pressed down
+//	        }
+//	    }
+//
+//	    // ...
+//	}
+//
+// The help information, which is not used in the example above, can be used
+// to render help text for keystrokes in your views.
+package key
+
+import (
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// Binding describes a set of keybindings and, optionally, their associated
+// help text.
+type Binding struct {
+	keys     []string
+	help     Help
+	disabled bool
+}
+
+// BindingOpt is an initialization option for a keybinding. It's used as an
+// argument to NewBinding.
+type BindingOpt func(*Binding)
+
+// NewBinding returns a new keybinding from a set of BindingOpt options.
+func NewBinding(opts ...BindingOpt) Binding {
+	b := &Binding{}
+	for _, opt := range opts {
+		opt(b)
+	}
+	return *b
+}
+
+// WithKeys initializes a keybinding with the given keystrokes.
+func WithKeys(keys ...string) BindingOpt {
+	return func(b *Binding) {
+		b.keys = keys
+	}
+}
+
+// WithHelp initializes a keybinding with the given help text.
+func WithHelp(key, desc string) BindingOpt {
+	return func(b *Binding) {
+		b.help = Help{Key: key, Desc: desc}
+	}
+}
+
+// WithDisabled initializes a disabled keybinding.
+func WithDisabled() BindingOpt {
+	return func(b *Binding) {
+		b.disabled = true
+	}
+}
+
+// SetKeys sets the keys for the keybinding.
+func (b *Binding) SetKeys(keys ...string) {
+	b.keys = keys
+}
+
+// Keys returns the keys for the keybinding.
+func (b Binding) Keys() []string {
+	return b.keys
+}
+
+// SetHelp sets the help text for the keybinding.
+func (b *Binding) SetHelp(key, desc string) {
+	b.help = Help{Key: key, Desc: desc}
+}
+
+// Help returns the Help information for the keybinding.
+func (b Binding) Help() Help {
+	return b.help
+}
+
+// Enabled returns whether or not the keybinding is enabled. Disabled
+// keybindings won't be activated and won't show up in help. Keybindings are
+// enabled by default.
+func (b Binding) Enabled() bool {
+	return !b.disabled && b.keys != nil
+}
+
+// SetEnabled enables or disables the keybinding.
+func (b *Binding) SetEnabled(v bool) {
+	b.disabled = !v
+}
+
+// Unbind removes the keys and help from this binding, effectively nullifying
+// it. This is a step beyond disabling it, since applications can enable
+// or disable key bindings based on application state.
+func (b *Binding) Unbind() {
+	b.keys = nil
+	b.help = Help{}
+}
+
+// Help is help information for a given keybinding.
+type Help struct {
+	Key  string
+	Desc string
+}
+
+// Matches checks if the given KeyMsg matches the given bindings.
+func Matches(k tea.KeyMsg, b ...Binding) bool {
+	keys := k.String()
+	for _, binding := range b {
+		for _, v := range binding.keys {
+			if keys == v && binding.Enabled() {
+				return true
+			}
+		}
+	}
+	return false
+}

key/key_test.go

@@ -0,0 +1,26 @@
+package key
+
+import (
+	"testing"
+)
+
+func TestBinding_Enabled(t *testing.T) {
+	binding := NewBinding(
+		WithKeys("k", "up"),
+		WithHelp("↑/k", "move up"),
+	)
+	if !binding.Enabled() {
+		t.Errorf("expected key to be Enabled")
+	}
+
+	binding.SetEnabled(false)
+	if binding.Enabled() {
+		t.Errorf("expected key not to be Enabled")
+	}
+
+	binding.SetEnabled(true)
+	binding.Unbind()
+	if binding.Enabled() {
+		t.Errorf("expected key not to be Enabled")
+	}
+}

list/defaultitem.go

@@ -0,0 +1,227 @@
+package list
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/charmbracelet/bubbles/key"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/muesli/reflow/truncate"
+)
+
+// DefaultItemStyles defines styling for a default list item.
+// See DefaultItemView for when these come into play.
+type DefaultItemStyles struct {
+	// The Normal state.
+	NormalTitle lipgloss.Style
+	NormalDesc  lipgloss.Style
+
+	// The selected item state.
+	SelectedTitle lipgloss.Style
+	SelectedDesc  lipgloss.Style
+
+	// The dimmed state, for when the filter input is initially activated.
+	DimmedTitle lipgloss.Style
+	DimmedDesc  lipgloss.Style
+
+	// Charcters matching the current filter, if any.
+	FilterMatch lipgloss.Style
+}
+
+// NewDefaultItemStyles returns style definitions for a default item. See
+// DefaultItemView for when these come into play.
+func NewDefaultItemStyles() (s DefaultItemStyles) {
+	s.NormalTitle = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#1a1a1a", Dark: "#dddddd"}).
+		Padding(0, 0, 0, 2)
+
+	s.NormalDesc = s.NormalTitle.Copy().
+		Foreground(lipgloss.AdaptiveColor{Light: "#A49FA5", Dark: "#777777"})
+
+	s.SelectedTitle = lipgloss.NewStyle().
+		Border(lipgloss.NormalBorder(), false, false, false, true).
+		BorderForeground(lipgloss.AdaptiveColor{Light: "#F793FF", Dark: "#AD58B4"}).
+		Foreground(lipgloss.AdaptiveColor{Light: "#EE6FF8", Dark: "#EE6FF8"}).
+		Padding(0, 0, 0, 1)
+
+	s.SelectedDesc = s.SelectedTitle.Copy().
+		Foreground(lipgloss.AdaptiveColor{Light: "#F793FF", Dark: "#AD58B4"})
+
+	s.DimmedTitle = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#A49FA5", Dark: "#777777"}).
+		Padding(0, 0, 0, 2)
+
+	s.DimmedDesc = s.DimmedTitle.Copy().
+		Foreground(lipgloss.AdaptiveColor{Light: "#C2B8C2", Dark: "#4D4D4D"})
+
+	s.FilterMatch = lipgloss.NewStyle().Underline(true)
+
+	return s
+}
+
+// DefaultItem describes an items designed to work with DefaultDelegate.
+type DefaultItem interface {
+	Item
+	Title() string
+	Description() string
+}
+
+// DefaultDelegate is a standard delegate designed to work in lists. It's
+// styled by DefaultItemStyles, which can be customized as you like.
+//
+// The description line can be hidden by setting Description to false, which
+// renders the list as single-line-items. The spacing between items can be set
+// with the SetSpacing method.
+//
+// Setting UpdateFunc is optional. If it's set it will be called when the
+// ItemDelegate called, which is called when the list's Update function is
+// invoked.
+//
+// Settings ShortHelpFunc and FullHelpFunc is optional. They can can be set to
+// include items in the list's default short and full help menus.
+type DefaultDelegate struct {
+	ShowDescription bool
+	Styles          DefaultItemStyles
+	UpdateFunc      func(tea.Msg, *Model) tea.Cmd
+	ShortHelpFunc   func() []key.Binding
+	FullHelpFunc    func() [][]key.Binding
+	height          int
+	spacing         int
+}
+
+// NewDefaultDelegate creates a new delegate with default styles.
+func NewDefaultDelegate() DefaultDelegate {
+	return DefaultDelegate{
+		ShowDescription: true,
+		Styles:          NewDefaultItemStyles(),
+		height:          2,
+		spacing:         1,
+	}
+}
+
+// SetHeight sets delegate's preferred height.
+func (d *DefaultDelegate) SetHeight(i int) {
+	d.height = i
+}
+
+// Height returns the delegate's preferred height.
+// This has effect only if ShowDescription is true,
+// otherwise height is always 1.
+func (d DefaultDelegate) Height() int {
+	if d.ShowDescription {
+		return d.height
+	}
+	return 1
+}
+
+// SetSpacing set the delegate's spacing.
+func (d *DefaultDelegate) SetSpacing(i int) {
+	d.spacing = i
+}
+
+// Spacing returns the delegate's spacing.
+func (d DefaultDelegate) Spacing() int {
+	return d.spacing
+}
+
+// Update checks whether the delegate's UpdateFunc is set and calls it.
+func (d DefaultDelegate) Update(msg tea.Msg, m *Model) tea.Cmd {
+	if d.UpdateFunc == nil {
+		return nil
+	}
+	return d.UpdateFunc(msg, m)
+}
+
+// Render prints an item.
+func (d DefaultDelegate) Render(w io.Writer, m Model, index int, item Item) {
+	var (
+		title, desc  string
+		matchedRunes []int
+		s            = &d.Styles
+	)
+
+	if i, ok := item.(DefaultItem); ok {
+		title = i.Title()
+		desc = i.Description()
+	} else {
+		return
+	}
+
+	if m.width <= 0 {
+		// short-circuit
+		return
+	}
+
+	// Prevent text from exceeding list width
+	textwidth := uint(m.width - s.NormalTitle.GetPaddingLeft() - s.NormalTitle.GetPaddingRight())
+	title = truncate.StringWithTail(title, textwidth, ellipsis)
+	if d.ShowDescription {
+		var lines []string
+		for i, line := range strings.Split(desc, "\n") {
+			if i >= d.height-1 {
+				break
+			}
+			lines = append(lines, truncate.StringWithTail(line, textwidth, ellipsis))
+		}
+		desc = strings.Join(lines, "\n")
+	}
+
+	// Conditions
+	var (
+		isSelected  = index == m.Index()
+		emptyFilter = m.FilterState() == Filtering && m.FilterValue() == ""
+		isFiltered  = m.FilterState() == Filtering || m.FilterState() == FilterApplied
+	)
+
+	if isFiltered && index < len(m.filteredItems) {
+		// Get indices of matched characters
+		matchedRunes = m.MatchesForItem(index)
+	}
+
+	if emptyFilter {
+		title = s.DimmedTitle.Render(title)
+		desc = s.DimmedDesc.Render(desc)
+	} else if isSelected && m.FilterState() != Filtering {
+		if isFiltered {
+			// Highlight matches
+			unmatched := s.SelectedTitle.Inline(true)
+			matched := unmatched.Copy().Inherit(s.FilterMatch)
+			title = lipgloss.StyleRunes(title, matchedRunes, matched, unmatched)
+		}
+		title = s.SelectedTitle.Render(title)
+		desc = s.SelectedDesc.Render(desc)
+	} else {
+		if isFiltered {
+			// Highlight matches
+			unmatched := s.NormalTitle.Inline(true)
+			matched := unmatched.Copy().Inherit(s.FilterMatch)
+			title = lipgloss.StyleRunes(title, matchedRunes, matched, unmatched)
+		}
+		title = s.NormalTitle.Render(title)
+		desc = s.NormalDesc.Render(desc)
+	}
+
+	if d.ShowDescription {
+		fmt.Fprintf(w, "%s\n%s", title, desc)
+		return
+	}
+	fmt.Fprintf(w, "%s", title)
+}
+
+// ShortHelp returns the delegate's short help.
+func (d DefaultDelegate) ShortHelp() []key.Binding {
+	if d.ShortHelpFunc != nil {
+		return d.ShortHelpFunc()
+	}
+	return nil
+}
+
+// FullHelp returns the delegate's full help.
+func (d DefaultDelegate) FullHelp() [][]key.Binding {
+	if d.FullHelpFunc != nil {
+		return d.FullHelpFunc()
+	}
+	return nil
+}

list/keys.go

@@ -0,0 +1,97 @@
+package list
+
+import "github.com/charmbracelet/bubbles/key"
+
+// KeyMap defines keybindings. It satisfies to the help.KeyMap interface, which
+// is used to render the menu menu.
+type KeyMap struct {
+	// Keybindings used when browsing the list.
+	CursorUp    key.Binding
+	CursorDown  key.Binding
+	NextPage    key.Binding
+	PrevPage    key.Binding
+	GoToStart   key.Binding
+	GoToEnd     key.Binding
+	Filter      key.Binding
+	ClearFilter key.Binding
+
+	// Keybindings used when setting a filter.
+	CancelWhileFiltering key.Binding
+	AcceptWhileFiltering key.Binding
+
+	// Help toggle keybindings.
+	ShowFullHelp  key.Binding
+	CloseFullHelp key.Binding
+
+	// The quit keybinding. This won't be caught when filtering.
+	Quit key.Binding
+
+	// The quit-no-matter-what keybinding. This will be caught when filtering.
+	ForceQuit key.Binding
+}
+
+// DefaultKeyMap returns a default set of keybindings.
+func DefaultKeyMap() KeyMap {
+	return KeyMap{
+		// Browsing.
+		CursorUp: key.NewBinding(
+			key.WithKeys("up", "k"),
+			key.WithHelp("↑/k", "up"),
+		),
+		CursorDown: key.NewBinding(
+			key.WithKeys("down", "j"),
+			key.WithHelp("↓/j", "down"),
+		),
+		PrevPage: key.NewBinding(
+			key.WithKeys("left", "h", "pgup", "b", "u"),
+			key.WithHelp("←/h/pgup", "prev page"),
+		),
+		NextPage: key.NewBinding(
+			key.WithKeys("right", "l", "pgdown", "f", "d"),
+			key.WithHelp("→/l/pgdn", "next page"),
+		),
+		GoToStart: key.NewBinding(
+			key.WithKeys("home", "g"),
+			key.WithHelp("g/home", "go to start"),
+		),
+		GoToEnd: key.NewBinding(
+			key.WithKeys("end", "G"),
+			key.WithHelp("G/end", "go to end"),
+		),
+		Filter: key.NewBinding(
+			key.WithKeys("/"),
+			key.WithHelp("/", "filter"),
+		),
+		ClearFilter: key.NewBinding(
+			key.WithKeys("esc"),
+			key.WithHelp("esc", "clear filter"),
+		),
+
+		// Filtering.
+		CancelWhileFiltering: key.NewBinding(
+			key.WithKeys("esc"),
+			key.WithHelp("esc", "cancel"),
+		),
+		AcceptWhileFiltering: key.NewBinding(
+			key.WithKeys("enter", "tab", "shift+tab", "ctrl+k", "up", "ctrl+j", "down"),
+			key.WithHelp("enter", "apply filter"),
+		),
+
+		// Toggle help.
+		ShowFullHelp: key.NewBinding(
+			key.WithKeys("?"),
+			key.WithHelp("?", "more"),
+		),
+		CloseFullHelp: key.NewBinding(
+			key.WithKeys("?"),
+			key.WithHelp("?", "close help"),
+		),
+
+		// Quitting.
+		Quit: key.NewBinding(
+			key.WithKeys("q", "esc"),
+			key.WithHelp("q", "quit"),
+		),
+		ForceQuit: key.NewBinding(key.WithKeys("ctrl+c")),
+	}
+}

list/list_test.go

@@ -0,0 +1,74 @@
+package list
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"testing"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+type item string
+
+func (i item) FilterValue() string { return "" }
+
+type itemDelegate struct{}
+
+func (d itemDelegate) Height() int                          { return 1 }
+func (d itemDelegate) Spacing() int                         { return 0 }
+func (d itemDelegate) Update(msg tea.Msg, m *Model) tea.Cmd { return nil }
+func (d itemDelegate) Render(w io.Writer, m Model, index int, listItem Item) {
+	i, ok := listItem.(item)
+	if !ok {
+		return
+	}
+
+	str := fmt.Sprintf("%d. %s", index+1, i)
+	fmt.Fprint(w, m.Styles.TitleBar.Render(str))
+}
+
+func TestStatusBarItemName(t *testing.T) {
+	list := New([]Item{item("foo"), item("bar")}, itemDelegate{}, 10, 10)
+	expected := "2 items"
+	if !strings.Contains(list.statusView(), expected) {
+		t.Fatalf("Error: expected view to contain %s", expected)
+	}
+
+	list.SetItems([]Item{item("foo")})
+	expected = "1 item"
+	if !strings.Contains(list.statusView(), expected) {
+		t.Fatalf("Error: expected view to contain %s", expected)
+	}
+}
+
+func TestStatusBarWithoutItems(t *testing.T) {
+	list := New([]Item{}, itemDelegate{}, 10, 10)
+
+	expected := "No items"
+	if !strings.Contains(list.statusView(), expected) {
+		t.Fatalf("Error: expected view to contain %s", expected)
+	}
+}
+
+func TestCustomStatusBarItemName(t *testing.T) {
+	list := New([]Item{item("foo"), item("bar")}, itemDelegate{}, 10, 10)
+	list.SetStatusBarItemName("connection", "connections")
+
+	expected := "2 connections"
+	if !strings.Contains(list.statusView(), expected) {
+		t.Fatalf("Error: expected view to contain %s", expected)
+	}
+
+	list.SetItems([]Item{item("foo")})
+	expected = "1 connection"
+	if !strings.Contains(list.statusView(), expected) {
+		t.Fatalf("Error: expected view to contain %s", expected)
+	}
+
+	list.SetItems([]Item{})
+	expected = "No connections"
+	if !strings.Contains(list.statusView(), expected) {
+		t.Fatalf("Error: expected view to contain %s", expected)
+	}
+}

list/style.go

@@ -0,0 +1,99 @@
+package list
+
+import (
+	"github.com/charmbracelet/lipgloss"
+)
+
+const (
+	bullet   = "•"
+	ellipsis = "…"
+)
+
+// Styles contains style definitions for this list component. By default, these
+// values are generated by DefaultStyles.
+type Styles struct {
+	TitleBar     lipgloss.Style
+	Title        lipgloss.Style
+	Spinner      lipgloss.Style
+	FilterPrompt lipgloss.Style
+	FilterCursor lipgloss.Style
+
+	// Default styling for matched characters in a filter. This can be
+	// overridden by delegates.
+	DefaultFilterCharacterMatch lipgloss.Style
+
+	StatusBar             lipgloss.Style
+	StatusEmpty           lipgloss.Style
+	StatusBarActiveFilter lipgloss.Style
+	StatusBarFilterCount  lipgloss.Style
+
+	NoItems lipgloss.Style
+
+	PaginationStyle lipgloss.Style
+	HelpStyle       lipgloss.Style
+
+	// Styled characters.
+	ActivePaginationDot   lipgloss.Style
+	InactivePaginationDot lipgloss.Style
+	ArabicPagination      lipgloss.Style
+	DividerDot            lipgloss.Style
+}
+
+// DefaultStyles returns a set of default style definitions for this list
+// component.
+func DefaultStyles() (s Styles) {
+	verySubduedColor := lipgloss.AdaptiveColor{Light: "#DDDADA", Dark: "#3C3C3C"}
+	subduedColor := lipgloss.AdaptiveColor{Light: "#9B9B9B", Dark: "#5C5C5C"}
+
+	s.TitleBar = lipgloss.NewStyle().Padding(0, 0, 1, 2)
+
+	s.Title = lipgloss.NewStyle().
+		Background(lipgloss.Color("62")).
+		Foreground(lipgloss.Color("230")).
+		Padding(0, 1)
+
+	s.Spinner = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#8E8E8E", Dark: "#747373"})
+
+	s.FilterPrompt = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#04B575", Dark: "#ECFD65"})
+
+	s.FilterCursor = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#EE6FF8", Dark: "#EE6FF8"})
+
+	s.DefaultFilterCharacterMatch = lipgloss.NewStyle().Underline(true)
+
+	s.StatusBar = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#A49FA5", Dark: "#777777"}).
+		Padding(0, 0, 1, 2)
+
+	s.StatusEmpty = lipgloss.NewStyle().Foreground(subduedColor)
+
+	s.StatusBarActiveFilter = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#1a1a1a", Dark: "#dddddd"})
+
+	s.StatusBarFilterCount = lipgloss.NewStyle().Foreground(verySubduedColor)
+
+	s.NoItems = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#909090", Dark: "#626262"})
+
+	s.ArabicPagination = lipgloss.NewStyle().Foreground(subduedColor)
+
+	s.PaginationStyle = lipgloss.NewStyle().PaddingLeft(2) //nolint:gomnd
+
+	s.HelpStyle = lipgloss.NewStyle().Padding(1, 0, 0, 2)
+
+	s.ActivePaginationDot = lipgloss.NewStyle().
+		Foreground(lipgloss.AdaptiveColor{Light: "#847A85", Dark: "#979797"}).
+		SetString(bullet)
+
+	s.InactivePaginationDot = lipgloss.NewStyle().
+		Foreground(verySubduedColor).
+		SetString(bullet)
+
+	s.DividerDot = lipgloss.NewStyle().
+		Foreground(verySubduedColor).
+		SetString(" " + bullet + " ")
+
+	return s
+}

paginator/paginator.go

@@ -7,6 +7,7 @@ package paginator
 import (
 	"fmt"
 
+	"github.com/charmbracelet/bubbles/key"
 	tea "github.com/charmbracelet/bubbletea"
 )
 
@@ -19,23 +20,52 @@ const (
 	Dots
 )
 
-// Model is the Bubble Tea model for this user interface.
-type Model struct {
-	Type              Type
-	Page              int
-	PerPage           int
-	TotalPages        int
-	ActiveDot         string
-	InactiveDot       string
-	ArabicFormat      string
-	UsePgUpPgDownKeys bool
-	UseLeftRightKeys  bool
-	UseUpDownKeys     bool
-	UseHLKeys         bool
-	UseJKKeys         bool
+// KeyMap is the key bindings for different actions within the paginator.
+type KeyMap struct {
+	PrevPage key.Binding
+	NextPage key.Binding
 }
 
-// SetTotalPages is a helper function for calculatng the total number of pages
+// DefaultKeyMap is the default set of key bindings for navigating and acting
+// upon the paginator.
+var DefaultKeyMap = KeyMap{
+	PrevPage: key.NewBinding(key.WithKeys("pgup", "left", "h")),
+	NextPage: key.NewBinding(key.WithKeys("pgdown", "right", "l")),
+}
+
+// Model is the Bubble Tea model for this user interface.
+type Model struct {
+	// Type configures how the pagination is rendered (Arabic, Dots).
+	Type Type
+	// Page is the current page number.
+	Page int
+	// PerPage is the number of items per page.
+	PerPage int
+	// TotalPages is the total number of pages.
+	TotalPages int
+	// ActiveDot is used to mark the current page under the Dots display type.
+	ActiveDot string
+	// InactiveDot is used to mark inactive pages under the Dots display type.
+	InactiveDot string
+	// ArabicFormat is the printf-style format to use for the Arabic display type.
+	ArabicFormat string
+
+	// KeyMap encodes the keybindings recognized by the widget.
+	KeyMap KeyMap
+
+	// Deprecated: customize KeyMap instead.
+	UsePgUpPgDownKeys bool
+	// Deprecated: customize KeyMap instead.
+	UseLeftRightKeys bool
+	// Deprecated: customize KeyMap instead.
+	UseUpDownKeys bool
+	// Deprecated: customize KeyMap instead.
+	UseHLKeys bool
+	// Deprecated: customize KeyMap instead.
+	UseJKKeys bool
+}
+
+// SetTotalPages is a helper function for calculating the total number of pages
 // from a given number of items. It's use is optional since this pager can be
 // used for other things beyond navigating sets. Note that it both returns the
 // number of total pages and alters the model.
@@ -65,10 +95,9 @@ func (m Model) ItemsOnPage(totalItems int) int {
 // of the slice you're rendering and you'll receive the start and end bounds
 // corresponding the to pagination. For example:
 //
-//     bunchOfStuff := []stuff{...}
-//     start, end := model.GetSliceBounds(len(bunchOfStuff))
-//     sliceToRender := bunchOfStuff[start:end]
-//
+//	bunchOfStuff := []stuff{...}
+//	start, end := model.GetSliceBounds(len(bunchOfStuff))
+//	sliceToRender := bunchOfStuff[start:end]
 func (m *Model) GetSliceBounds(length int) (start int, end int) {
 	start = m.Page * m.PerPage
 	end = min(m.Page*m.PerPage+m.PerPage, length)
@@ -96,67 +125,34 @@ func (m Model) OnLastPage() bool {
 	return m.Page == m.TotalPages-1
 }
 
-// NewModel creates a new model with defaults.
-func NewModel() Model {
+// New creates a new model with defaults.
+func New() Model {
 	return Model{
-		Type:              Arabic,
-		Page:              0,
-		PerPage:           1,
-		TotalPages:        1,
-		ActiveDot:         "•",
-		InactiveDot:       "○",
-		ArabicFormat:      "%d/%d",
-		UsePgUpPgDownKeys: true,
-		UseLeftRightKeys:  true,
-		UseUpDownKeys:     false,
-		UseHLKeys:         true,
-		UseJKKeys:         false,
+		Type:         Arabic,
+		Page:         0,
+		PerPage:      1,
+		TotalPages:   1,
+		KeyMap:       DefaultKeyMap,
+		ActiveDot:    "•",
+		InactiveDot:  "○",
+		ArabicFormat: "%d/%d",
 	}
 }
 
+// NewModel creates a new model with defaults.
+//
+// Deprecated. Use New instead.
+var NewModel = New
+
 // Update is the Tea update function which binds keystrokes to pagination.
 func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
-		if m.UsePgUpPgDownKeys {
-			switch msg.String() {
-			case "pgup":
-				m.PrevPage()
-			case "pgdown":
-				m.NextPage()
-			}
-		}
-		if m.UseLeftRightKeys {
-			switch msg.String() {
-			case "left":
-				m.PrevPage()
-			case "right":
-				m.NextPage()
-			}
-		}
-		if m.UseUpDownKeys {
-			switch msg.String() {
-			case "up":
-				m.PrevPage()
-			case "down":
-				m.NextPage()
-			}
-		}
-		if m.UseHLKeys {
-			switch msg.String() {
-			case "h":
-				m.PrevPage()
-			case "l":
-				m.NextPage()
-			}
-		}
-		if m.UseJKKeys {
-			switch msg.String() {
-			case "j":
-				m.PrevPage()
-			case "k":
-				m.NextPage()
-			}
+		switch {
+		case key.Matches(msg, m.KeyMap.NextPage):
+			m.NextPage()
+		case key.Matches(msg, m.KeyMap.PrevPage):
+			m.PrevPage()
 		}
 	}
 

progress/progress.go

@@ -2,24 +2,48 @@ package progress
 
 import (
 	"fmt"
+	"math"
 	"strings"
+	"sync"
+	"time"
 
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/harmonica"
+	"github.com/charmbracelet/lipgloss"
 	"github.com/lucasb-eyer/go-colorful"
 	"github.com/muesli/reflow/ansi"
 	"github.com/muesli/termenv"
 )
 
-const defaultWidth = 40
+// Internal ID management. Used during animating to assure that frame messages
+// can only be received by progress components that sent them.
+var (
+	lastID int
+	idMtx  sync.Mutex
+)
 
-var color func(string) termenv.Color = termenv.ColorProfile().Color
+// Return the next ID we should use on the model.
+func nextID() int {
+	idMtx.Lock()
+	defer idMtx.Unlock()
+	lastID++
+	return lastID
+}
 
-// Option is used to set options in NewModel. For example:
+const (
+	fps              = 60
+	defaultWidth     = 40
+	defaultFrequency = 18.0
+	defaultDamping   = 1.0
+)
+
+// Option is used to set options in New. For example:
 //
-//     progress := NewModel(
-//	       WithRamp("#ff0000", "#0000ff"),
-//	       WithoutPercentage(),
-//     )
-type Option func(*Model) error
+//	    progress := New(
+//		       WithRamp("#ff0000", "#0000ff"),
+//		       WithoutPercentage(),
+//	    )
+type Option func(*Model)
 
 // WithDefaultGradient sets a gradient fill with default colors.
 func WithDefaultGradient() Option {
@@ -28,8 +52,8 @@ func WithDefaultGradient() Option {
 
 // WithGradient sets a gradient fill blending between two colors.
 func WithGradient(colorA, colorB string) Option {
-	return func(m *Model) error {
-		return m.setRamp(colorA, colorB, false)
+	return func(m *Model) {
+		m.setRamp(colorA, colorB, false)
 	}
 }
 
@@ -42,25 +66,23 @@ func WithDefaultScaledGradient() Option {
 // WithScaledGradient scales the gradient to fit the width of the filled portion of
 // the progress bar.
 func WithScaledGradient(colorA, colorB string) Option {
-	return func(m *Model) error {
-		return m.setRamp(colorA, colorB, true)
+	return func(m *Model) {
+		m.setRamp(colorA, colorB, true)
 	}
 }
 
 // WithSolidFill sets the progress to use a solid fill with the given color.
 func WithSolidFill(color string) Option {
-	return func(m *Model) error {
+	return func(m *Model) {
 		m.FullColor = color
 		m.useRamp = false
-		return nil
 	}
 }
 
 // WithoutPercentage hides the numeric percentage.
 func WithoutPercentage() Option {
-	return func(m *Model) error {
+	return func(m *Model) {
 		m.ShowPercentage = false
-		return nil
 	}
 }
 
@@ -68,31 +90,69 @@ func WithoutPercentage() Option {
 // set the width via the Width property, which can come in handy if you're
 // waiting for a tea.WindowSizeMsg.
 func WithWidth(w int) Option {
-	return func(m *Model) error {
+	return func(m *Model) {
 		m.Width = w
-		return nil
 	}
 }
 
+// WithSpringOptions sets the initial frequency and damping options for the
+// progressbar's built-in spring-based animation. Frequency corresponds to
+// speed, and damping to bounciness. For details see:
+//
+// https://github.com/charmbracelet/harmonica
+func WithSpringOptions(frequency, damping float64) Option {
+	return func(m *Model) {
+		m.SetSpringOptions(frequency, damping)
+		m.springCustomized = true
+	}
+}
+
+// WithColorProfile sets the color profile to use for the progress bar.
+func WithColorProfile(p termenv.Profile) Option {
+	return func(m *Model) {
+		m.colorProfile = p
+	}
+}
+
+// FrameMsg indicates that an animation step should occur.
+type FrameMsg struct {
+	id  int
+	tag int
+}
+
 // Model stores values we'll use when rendering the progress bar.
 type Model struct {
+	// An identifier to keep us from receiving messages intended for other
+	// progress bars.
+	id int
+
+	// An identifier to keep us from receiving frame messages too quickly.
+	tag int
 
 	// Total width of the progress bar, including percentage, if set.
 	Width int
 
-	// "Filled" sections of the progress bar
+	// "Filled" sections of the progress bar.
 	Full      rune
 	FullColor string
 
-	// "Empty" sections of progress bar
+	// "Empty" sections of progress bar.
 	Empty      rune
 	EmptyColor string
 
-	// Settings for rendering the numeric percentage
+	// Settings for rendering the numeric percentage.
 	ShowPercentage  bool
 	PercentFormat   string // a fmt string for a float
-	PercentageStyle *termenv.Style
+	PercentageStyle lipgloss.Style
 
+	// Members for animated transitions.
+	spring           harmonica.Spring
+	springCustomized bool
+	percentShown     float64 // percent currently displaying
+	targetPercent    float64 // percent to which we're animating
+	velocity         float64
+
+	// Gradient settings
 	useRamp    bool
 	rampColorA colorful.Color
 	rampColorB colorful.Color
@@ -101,11 +161,15 @@ type Model struct {
 	// of the progress bar. When false, the width of the gradient will be set
 	// to the full width of the progress bar.
 	scaleRamp bool
+
+	// Color profile for the progress bar.
+	colorProfile termenv.Profile
 }
 
-// NewModel returns a model with default values.
-func NewModel(opts ...Option) (*Model, error) {
-	m := &Model{
+// New returns a model with default values.
+func New(opts ...Option) Model {
+	m := Model{
+		id:             nextID(),
 		Width:          defaultWidth,
 		Full:           '█',
 		FullColor:      "#7571F9",
@@ -113,40 +177,125 @@ func NewModel(opts ...Option) (*Model, error) {
 		EmptyColor:     "#606060",
 		ShowPercentage: true,
 		PercentFormat:  " %3.0f%%",
+		colorProfile:   termenv.ColorProfile(),
+	}
+	if !m.springCustomized {
+		m.SetSpringOptions(defaultFrequency, defaultDamping)
 	}
 
 	for _, opt := range opts {
-		if err := opt(m); err != nil {
-			return nil, err
-		}
+		opt(&m)
 	}
-
-	return m, nil
+	return m
 }
 
-// View renders the progress bar as a given percentage.
-func (m Model) View(percent float64) string {
-	b := strings.Builder{}
-	if m.ShowPercentage {
-		percentage := fmt.Sprintf(m.PercentFormat, percent*100) //nolint:gomnd
-		if m.PercentageStyle != nil {
-			percentage = m.PercentageStyle.Styled(percentage)
+// NewModel returns a model with default values.
+//
+// Deprecated. Use New instead.
+var NewModel = New
+
+// Init exists satisfy the tea.Model interface.
+func (m Model) Init() tea.Cmd {
+	return nil
+}
+
+// Update is used to animation the progress bar during transitions. Use
+// SetPercent to create the command you'll need to trigger the animation.
+//
+// If you're rendering with ViewAs you won't need this.
+func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case FrameMsg:
+		if msg.id != m.id || msg.tag != m.tag {
+			return m, nil
 		}
-		m.bar(&b, percent, ansi.PrintableRuneWidth(percentage))
-		b.WriteString(percentage)
-	} else {
-		m.bar(&b, percent, 0)
+
+		// If we've more or less reached equilibrium, stop updating.
+		dist := math.Abs(m.percentShown - m.targetPercent)
+		if dist < 0.001 && m.velocity < 0.01 {
+			return m, nil
+		}
+
+		m.percentShown, m.velocity = m.spring.Update(m.percentShown, m.velocity, m.targetPercent)
+		return m, m.nextFrame()
+
+	default:
+		return m, nil
 	}
+}
+
+// SetSpringOptions sets the frequency and damping for the current spring.
+// Frequency corresponds to speed, and damping to bounciness. For details see:
+//
+// https://github.com/charmbracelet/harmonica
+func (m *Model) SetSpringOptions(frequency, damping float64) {
+	m.spring = harmonica.NewSpring(harmonica.FPS(fps), frequency, damping)
+}
+
+// Percent returns the current visible percentage on the model. This is only
+// relevant when you're animating the progress bar.
+//
+// If you're rendering with ViewAs you won't need this.
+func (m Model) Percent() float64 {
+	return m.targetPercent
+}
+
+// SetPercent sets the percentage state of the model as well as a command
+// necessary for animating the progress bar to this new percentage.
+//
+// If you're rendering with ViewAs you won't need this.
+func (m *Model) SetPercent(p float64) tea.Cmd {
+	m.targetPercent = math.Max(0, math.Min(1, p))
+	m.tag++
+	return m.nextFrame()
+}
+
+// IncrPercent increments the percentage by a given amount, returning a command
+// necessary to animate the progress bar to the new percentage.
+//
+// If you're rendering with ViewAs you won't need this.
+func (m *Model) IncrPercent(v float64) tea.Cmd {
+	return m.SetPercent(m.Percent() + v)
+}
+
+// DecrPercent decrements the percentage by a given amount, returning a command
+// necessary to animate the progress bar to the new percentage.
+//
+// If you're rendering with ViewAs you won't need this.
+func (m *Model) DecrPercent(v float64) tea.Cmd {
+	return m.SetPercent(m.Percent() - v)
+}
+
+// View renders the an animated progress bar in its current state. To render
+// a static progress bar based on your own calculations use ViewAs instead.
+func (m Model) View() string {
+	return m.ViewAs(m.percentShown)
+}
+
+// ViewAs renders the progress bar with a given percentage.
+func (m Model) ViewAs(percent float64) string {
+	b := strings.Builder{}
+	percentView := m.percentageView(percent)
+	m.barView(&b, percent, ansi.PrintableRuneWidth(percentView))
+	b.WriteString(percentView)
 	return b.String()
 }
 
-func (m Model) bar(b *strings.Builder, percent float64, textWidth int) {
+func (m *Model) nextFrame() tea.Cmd {
+	return tea.Tick(time.Second/time.Duration(fps), func(time.Time) tea.Msg {
+		return FrameMsg{id: m.id, tag: m.tag}
+	})
+}
+
+func (m Model) barView(b *strings.Builder, percent float64, textWidth int) {
 	var (
-		tw = m.Width - textWidth        // total width
-		fw = int(float64(tw) * percent) // filled width
+		tw = max(0, m.Width-textWidth)                // total width
+		fw = int(math.Round((float64(tw) * percent))) // filled width
 		p  float64
 	)
 
+	fw = max(0, min(tw, fw))
+
 	if m.useRamp {
 		// Gradient fill
 		for i := 0; i < fw; i++ {
@@ -158,35 +307,59 @@ func (m Model) bar(b *strings.Builder, percent float64, textWidth int) {
 			c := m.rampColorA.BlendLuv(m.rampColorB, p).Hex()
 			b.WriteString(termenv.
 				String(string(m.Full)).
-				Foreground(color(c)).
+				Foreground(m.color(c)).
 				String(),
 			)
 		}
 	} else {
 		// Solid fill
-		s := termenv.String(string(m.Full)).Foreground(color(m.FullColor)).String()
+		s := termenv.String(string(m.Full)).Foreground(m.color(m.FullColor)).String()
 		b.WriteString(strings.Repeat(s, fw))
 	}
 
 	// Empty fill
-	e := termenv.String(string(m.Empty)).Foreground(color(m.EmptyColor)).String()
-	b.WriteString(strings.Repeat(e, tw-fw))
+	e := termenv.String(string(m.Empty)).Foreground(m.color(m.EmptyColor)).String()
+	n := max(0, tw-fw)
+	b.WriteString(strings.Repeat(e, n))
 }
 
-func (m *Model) setRamp(colorA, colorB string, scaled bool) error {
-	a, err := colorful.Hex(colorA)
-	if err != nil {
-		return err
+func (m Model) percentageView(percent float64) string {
+	if !m.ShowPercentage {
+		return ""
 	}
+	percent = math.Max(0, math.Min(1, percent))
+	percentage := fmt.Sprintf(m.PercentFormat, percent*100) //nolint:gomnd
+	percentage = m.PercentageStyle.Inline(true).Render(percentage)
+	return percentage
+}
 
-	b, err := colorful.Hex(colorB)
-	if err != nil {
-		return err
-	}
+func (m *Model) setRamp(colorA, colorB string, scaled bool) {
+	// In the event of an error colors here will default to black. For
+	// usability's sake, and because such an error is only cosmetic, we're
+	// ignoring the error for sake of usability.
+	a, _ := colorful.Hex(colorA)
+	b, _ := colorful.Hex(colorB)
 
 	m.useRamp = true
 	m.scaleRamp = scaled
 	m.rampColorA = a
 	m.rampColorB = b
-	return nil
+}
+
+func (m Model) color(c string) termenv.Color {
+	return m.colorProfile.Color(c)
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
 }

spinner/spinner.go

@@ -1,14 +1,28 @@
 package spinner
 
 import (
-	"strings"
+	"sync"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
-	"github.com/muesli/reflow/ansi"
 )
 
+// Internal ID management. Used during animating to ensure that frame messages
+// are received only by spinner components that sent them.
+var (
+	lastID int
+	idMtx  sync.Mutex
+)
+
+// Return the next ID we should use on the Model.
+func nextID() int {
+	idMtx.Lock()
+	defer idMtx.Unlock()
+	lastID++
+	return lastID
+}
+
 // Spinner is a set of frames used in animating the spinner.
 type Spinner struct {
 	Frames []string
@@ -53,12 +67,27 @@ var (
 		Frames: []string{"🙈", "🙉", "🙊"},
 		FPS:    time.Second / 3, //nolint:gomnd
 	}
+	Meter = Spinner{
+		Frames: []string{
+			"▱▱▱",
+			"▰▱▱",
+			"▰▰▱",
+			"▰▰▰",
+			"▰▰▱",
+			"▰▱▱",
+			"▱▱▱",
+		},
+		FPS: time.Second / 7, //nolint:gomnd
+	}
+	Hamburger = Spinner{
+		Frames: []string{"☱", "☲", "☴", "☲"},
+		FPS:    time.Second / 3, //nolint:gomnd
+	}
 )
 
-// Model contains the state for the spinner. Use NewModel to create new models
+// Model contains the state for the spinner. Use New to create new models
 // rather than using Model as a struct literal.
 type Model struct {
-
 	// Spinner settings to use. See type Spinner.
 	Spinner Spinner
 
@@ -69,129 +98,55 @@ type Model struct {
 	// https://github.com/charmbracelet/lipgloss
 	Style lipgloss.Style
 
-	// MinimumLifetime is the minimum amount of time the spinner can run. Any
-	// logic around this can be implemented in view that implements this
-	// spinner. If HideFor is set MinimumLifetime will be added on top of
-	// HideFor. In other words, if HideFor is 100ms and MinimumLifetime is
-	// 200ms then MinimumLifetime will expire after 300ms.
-	//
-	// MinimumLifetime is optional.
-	//
-	// This is considered experimental and may not appear in future versions of
-	// this library.
-	MinimumLifetime time.Duration
-
-	// HideFor can be used to wait to show the spinner until a certain amount
-	// of time has passed. This can be useful for preventing flicking when load
-	// times are very fast.
-	// Optional.
-	//
-	// This is considered experimental and may not appear in future versions of
-	// this library.
-	HideFor time.Duration
-
-	frame     int
-	startTime time.Time
-	tag       int
+	frame int
+	id    int
+	tag   int
 }
 
-// Start resets resets the spinner start time. For use with MinimumLifetime and
-// MinimumStartTime. Optional.
-//
-// This function is optional and generally considered for advanced use only.
-// Most of the time your application logic will obviate the need for this
-// method.
-//
-// This is considered experimental and may not appear in future versions of
-// this library.
-func (m *Model) Start() {
-	m.startTime = time.Now()
+// ID returns the spinner's unique ID.
+func (m Model) ID() int {
+	return m.id
 }
 
-// Finish sets the internal timer to a completed state so long as the spinner
-// isn't flagged to be showing. If it is showing, finish has no effect. The
-// idea here is that you call Finish if your operation has completed and, if
-// the spinner isn't showing yet (by virtue of HideFor) then Visible() doesn't
-// show the spinner at all.
-//
-// This is intended to work in conjunction with MinimumLifetime and
-// MinimumStartTime, is completely optional.
-//
-// This function is optional and generally considered for advanced use only.
-// Most of the time your application logic will obviate the need for this
-// method.
-//
-// This is considered experimental and may not appear in future versions of
-// this library.
-func (m *Model) Finish() {
-	if m.hidden() {
-		m.startTime = time.Time{}
+// New returns a model with default values.
+func New(opts ...Option) Model {
+	m := Model{
+		Spinner: Line,
+		id:      nextID(),
 	}
-}
 
-// advancedMode returns whether or not the user is making use of HideFor and
-// MinimumLifetime properties.
-func (m Model) advancedMode() bool {
-	return m.HideFor > 0 && m.MinimumLifetime > 0
-}
-
-// hidden returns whether or not Model.HideFor is in effect.
-func (m Model) hidden() bool {
-	if m.startTime.IsZero() {
-		return false
+	for _, opt := range opts {
+		opt(&m)
 	}
-	if m.HideFor == 0 {
-		return false
-	}
-	return m.startTime.Add(m.HideFor).After(time.Now())
-}
 
-// finished returns whether the minimum lifetime of this spinner has been
-// exceeded.
-func (m Model) finished() bool {
-	if m.startTime.IsZero() || m.MinimumLifetime == 0 {
-		return true
-	}
-	return m.startTime.Add(m.HideFor).Add(m.MinimumLifetime).Before(time.Now())
-}
-
-// Visible returns whether or not the view should be rendered. Works in
-// conjunction with Model.HideFor and Model.MinimumLifetimeReached. You should
-// use this method directly to determine whether or not to render this view in
-// the parent view and whether to continue sending spin messaging in the
-// parent update function.
-//
-// This function is optional and generally considered for advanced use only.
-// Most of the time your application logic will obviate the need for this
-// method.
-//
-// This is considered experimental and may not appear in future versions of
-// this library.
-func (m Model) Visible() bool {
-	return !m.hidden() && !m.finished()
+	return m
 }
 
 // NewModel returns a model with default values.
-func NewModel() Model {
-	return Model{Spinner: Line}
-}
+//
+// Deprecated. Use New instead.
+var NewModel = New
 
 // TickMsg indicates that the timer has ticked and we should render a frame.
 type TickMsg struct {
 	Time time.Time
 	tag  int
+	ID   int
 }
 
-// Update is the Tea update function. This will advance the spinner one frame
-// every time it's called, regardless the message passed, so be sure the logic
-// is setup so as not to call this Update needlessly.
+// Update is the Tea update function.
 func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 	switch msg := msg.(type) {
 	case TickMsg:
+		// If an ID is set, and the ID doesn't belong to this spinner, reject
+		// the message.
+		if msg.ID > 0 && msg.ID != m.id {
+			return m, nil
+		}
 
 		// If a tag is set, and it's not the one we expect, reject the message.
 		// This prevents the spinner from receiving too many messages and
-		// this spinning too fast.
+		// thus spinning too fast.
 		if msg.tag > 0 && msg.tag != m.tag {
 			return m, nil
 		}
@@ -202,7 +157,7 @@ func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 		}
 
 		m.tag++
-		return m, m.tick(m.tag)
+		return m, m.tick(m.id, m.tag)
 	default:
 		return m, nil
 	}
@@ -214,29 +169,58 @@ func (m Model) View() string {
 		return "(error)"
 	}
 
-	frame := m.Spinner.Frames[m.frame]
-
-	// If we're using the fine-grained hide/show spinner rules and those rules
-	// deem that the spinner should be hidden, draw an empty space in place of
-	// the spinner.
-	if m.advancedMode() && !m.Visible() {
-		frame = strings.Repeat(" ", ansi.PrintableRuneWidth(frame))
-	}
-
-	return m.Style.Render(frame)
+	return m.Style.Render(m.Spinner.Frames[m.frame])
 }
 
 // Tick is the command used to advance the spinner one frame. Use this command
 // to effectively start the spinner.
-func Tick() tea.Msg {
-	return TickMsg{Time: time.Now()}
+func (m Model) Tick() tea.Msg {
+	return TickMsg{
+		// The time at which the tick occurred.
+		Time: time.Now(),
+
+		// The ID of the spinner that this message belongs to. This can be
+		// helpful when routing messages, however bear in mind that spinners
+		// will ignore messages that don't contain ID by default.
+		ID: m.id,
+
+		tag: m.tag,
+	}
 }
 
-func (m Model) tick(tag int) tea.Cmd {
+func (m Model) tick(id, tag int) tea.Cmd {
 	return tea.Tick(m.Spinner.FPS, func(t time.Time) tea.Msg {
 		return TickMsg{
 			Time: t,
+			ID:   id,
 			tag:  tag,
 		}
 	})
 }
+
+// Tick is the command used to advance the spinner one frame. Use this command
+// to effectively start the spinner.
+//
+// This method is deprecated. Use Model.Tick instead.
+func Tick() tea.Msg {
+	return TickMsg{Time: time.Now()}
+}
+
+// Option is used to set options in New. For example:
+//
+//	spinner := New(WithSpinner(Dot))
+type Option func(*Model)
+
+// WithSpinner is an option to set the spinner.
+func WithSpinner(spinner Spinner) Option {
+	return func(m *Model) {
+		m.Spinner = spinner
+	}
+}
+
+// WithStyle is an option to set the spinner style.
+func WithStyle(style lipgloss.Style) Option {
+	return func(m *Model) {
+		m.Style = style
+	}
+}

spinner/spinner_test.go

@@ -0,0 +1,61 @@
+package spinner_test
+
+import (
+	"testing"
+
+	"github.com/charmbracelet/bubbles/spinner"
+)
+
+func TestSpinnerNew(t *testing.T) {
+	assertEqualSpinner := func(t *testing.T, exp, got spinner.Spinner) {
+		t.Helper()
+
+		if exp.FPS != got.FPS {
+			t.Errorf("expecting %d FPS, got %d", exp.FPS, got.FPS)
+		}
+
+		if e, g := len(exp.Frames), len(got.Frames); e != g {
+			t.Fatalf("expecting %d frames, got %d", e, g)
+		}
+
+		for i, e := range exp.Frames {
+			if g := got.Frames[i]; e != g {
+				t.Errorf("expecting frame index %d with value %q, got %q", i, e, g)
+			}
+		}
+	}
+	t.Run("default", func(t *testing.T) {
+		s := spinner.New()
+
+		assertEqualSpinner(t, spinner.Line, s.Spinner)
+	})
+
+	t.Run("WithSpinner", func(t *testing.T) {
+		customSpinner := spinner.Spinner{
+			Frames: []string{"a", "b", "c", "d"},
+			FPS:    16,
+		}
+
+		s := spinner.New(spinner.WithSpinner(customSpinner))
+
+		assertEqualSpinner(t, customSpinner, s.Spinner)
+	})
+
+	tests := map[string]spinner.Spinner{
+		"Line":    spinner.Line,
+		"Dot":     spinner.Dot,
+		"MiniDot": spinner.MiniDot,
+		"Jump":    spinner.Jump,
+		"Pulse":   spinner.Pulse,
+		"Points":  spinner.Points,
+		"Globe":   spinner.Globe,
+		"Moon":    spinner.Moon,
+		"Monkey":  spinner.Monkey,
+	}
+
+	for name, s := range tests {
+		t.Run(name, func(t *testing.T) {
+			assertEqualSpinner(t, spinner.New(spinner.WithSpinner(s)).Spinner, s)
+		})
+	}
+}

stopwatch/stopwatch.go

@@ -0,0 +1,152 @@
+// Package stopwatch provides a simple stopwatch component.
+package stopwatch
+
+import (
+	"sync"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+var (
+	lastID int
+	idMtx  sync.Mutex
+)
+
+func nextID() int {
+	idMtx.Lock()
+	defer idMtx.Unlock()
+	lastID++
+	return lastID
+}
+
+// TickMsg is a message that is sent on every timer tick.
+type TickMsg struct {
+	// ID is the identifier of the stopwatch that send the message. This makes
+	// it possible to determine which stopwatch a tick belongs to when there
+	// are multiple stopwatches running.
+	//
+	// Note, however, that a stopwatch will reject ticks from other
+	// stopwatches, so it's safe to flow all TickMsgs through all stopwatches
+	// and have them still behave appropriately.
+	ID int
+}
+
+// StartStopMsg is sent when the stopwatch should start or stop.
+type StartStopMsg struct {
+	ID      int
+	running bool
+}
+
+// ResetMsg is sent when the stopwatch should reset.
+type ResetMsg struct {
+	ID int
+}
+
+// Model for the stopwatch component.
+type Model struct {
+	d       time.Duration
+	id      int
+	running bool
+
+	// How long to wait before every tick. Defaults to 1 second.
+	Interval time.Duration
+}
+
+// NewWithInterval creates a new stopwatch with the given timeout and tick
+// interval.
+func NewWithInterval(interval time.Duration) Model {
+	return Model{
+		Interval: interval,
+		id:       nextID(),
+	}
+}
+
+// New creates a new stopwatch with 1s interval.
+func New() Model {
+	return NewWithInterval(time.Second)
+}
+
+// ID returns the unique ID of the model.
+func (m Model) ID() int {
+	return m.id
+}
+
+// Init starts the stopwatch.
+func (m Model) Init() tea.Cmd {
+	return m.Start()
+}
+
+// Start starts the stopwatch.
+func (m Model) Start() tea.Cmd {
+	return tea.Batch(func() tea.Msg {
+		return StartStopMsg{ID: m.id, running: true}
+	}, tick(m.id, m.Interval))
+}
+
+// Stop stops the stopwatch.
+func (m Model) Stop() tea.Cmd {
+	return func() tea.Msg {
+		return StartStopMsg{ID: m.id, running: false}
+	}
+}
+
+// Toggle stops the stopwatch if it is running and starts it if it is stopped.
+func (m Model) Toggle() tea.Cmd {
+	if m.Running() {
+		return m.Stop()
+	}
+	return m.Start()
+}
+
+// Reset restes the stopwatch to 0.
+func (m Model) Reset() tea.Cmd {
+	return func() tea.Msg {
+		return ResetMsg{ID: m.id}
+	}
+}
+
+// Running returns true if the stopwatch is running or false if it is stopped.
+func (m Model) Running() bool {
+	return m.running
+}
+
+// Update handles the timer tick.
+func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case StartStopMsg:
+		if msg.ID != m.id {
+			return m, nil
+		}
+		m.running = msg.running
+	case ResetMsg:
+		if msg.ID != m.id {
+			return m, nil
+		}
+		m.d = 0
+	case TickMsg:
+		if !m.running || msg.ID != m.id {
+			break
+		}
+		m.d += m.Interval
+		return m, tick(m.id, m.Interval)
+	}
+
+	return m, nil
+}
+
+// Elapsed returns the time elapsed.
+func (m Model) Elapsed() time.Duration {
+	return m.d
+}
+
+// View of the timer component.
+func (m Model) View() string {
+	return m.d.String()
+}
+
+func tick(id int, d time.Duration) tea.Cmd {
+	return tea.Tick(d, func(_ time.Time) tea.Msg {
+		return TickMsg{ID: id}
+	})
+}

table/table.go

@@ -0,0 +1,392 @@
+package table
+
+import (
+	"strings"
+
+	"github.com/charmbracelet/bubbles/key"
+	"github.com/charmbracelet/bubbles/viewport"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/mattn/go-runewidth"
+)
+
+// Model defines a state for the table widget.
+type Model struct {
+	KeyMap KeyMap
+
+	cols   []Column
+	rows   []Row
+	cursor int
+	focus  bool
+	styles Styles
+
+	viewport viewport.Model
+}
+
+// Row represents one line in the table.
+type Row []string
+
+// Column defines the table structure.
+type Column struct {
+	Title string
+	Width int
+}
+
+// KeyMap defines keybindings. It satisfies to the help.KeyMap interface, which
+// is used to render the menu menu.
+type KeyMap struct {
+	LineUp       key.Binding
+	LineDown     key.Binding
+	PageUp       key.Binding
+	PageDown     key.Binding
+	HalfPageUp   key.Binding
+	HalfPageDown key.Binding
+	GotoTop      key.Binding
+	GotoBottom   key.Binding
+}
+
+// DefaultKeyMap returns a default set of keybindings.
+func DefaultKeyMap() KeyMap {
+	const spacebar = " "
+	return KeyMap{
+		LineUp: key.NewBinding(
+			key.WithKeys("up", "k"),
+			key.WithHelp("↑/k", "up"),
+		),
+		LineDown: key.NewBinding(
+			key.WithKeys("down", "j"),
+			key.WithHelp("↓/j", "down"),
+		),
+		PageUp: key.NewBinding(
+			key.WithKeys("b", "pgup"),
+			key.WithHelp("b/pgup", "page up"),
+		),
+		PageDown: key.NewBinding(
+			key.WithKeys("f", "pgdown", spacebar),
+			key.WithHelp("f/pgdn", "page down"),
+		),
+		HalfPageUp: key.NewBinding(
+			key.WithKeys("u", "ctrl+u"),
+			key.WithHelp("u", "½ page up"),
+		),
+		HalfPageDown: key.NewBinding(
+			key.WithKeys("d", "ctrl+d"),
+			key.WithHelp("d", "½ page down"),
+		),
+		GotoTop: key.NewBinding(
+			key.WithKeys("home", "g"),
+			key.WithHelp("g/home", "go to start"),
+		),
+		GotoBottom: key.NewBinding(
+			key.WithKeys("end", "G"),
+			key.WithHelp("G/end", "go to end"),
+		),
+	}
+}
+
+// Styles contains style definitions for this list component. By default, these
+// values are generated by DefaultStyles.
+type Styles struct {
+	Header   lipgloss.Style
+	Cell     lipgloss.Style
+	Selected lipgloss.Style
+}
+
+// DefaultStyles returns a set of default style definitions for this table.
+func DefaultStyles() Styles {
+	return Styles{
+		Selected: lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("212")),
+		Header:   lipgloss.NewStyle().Bold(true).Padding(0, 1),
+		Cell:     lipgloss.NewStyle().Padding(0, 1),
+	}
+}
+
+// SetStyles sets the table styles.
+func (m *Model) SetStyles(s Styles) {
+	m.styles = s
+	m.UpdateViewport()
+}
+
+// Option is used to set options in New. For example:
+//
+//	table := New(WithColumns([]Column{{Title: "ID", Width: 10}}))
+type Option func(*Model)
+
+// New creates a new model for the table widget.
+func New(opts ...Option) Model {
+	m := Model{
+		cursor:   0,
+		viewport: viewport.New(0, 20),
+
+		KeyMap: DefaultKeyMap(),
+		styles: DefaultStyles(),
+	}
+
+	for _, opt := range opts {
+		opt(&m)
+	}
+
+	m.UpdateViewport()
+
+	return m
+}
+
+// WithColumns sets the table columns (headers).
+func WithColumns(cols []Column) Option {
+	return func(m *Model) {
+		m.cols = cols
+	}
+}
+
+// WithRows sets the table rows (data).
+func WithRows(rows []Row) Option {
+	return func(m *Model) {
+		m.rows = rows
+	}
+}
+
+// WithHeight sets the height of the table.
+func WithHeight(h int) Option {
+	return func(m *Model) {
+		m.viewport.Height = h
+	}
+}
+
+// WithWidth sets the width of the table.
+func WithWidth(w int) Option {
+	return func(m *Model) {
+		m.viewport.Width = w
+	}
+}
+
+// WithFocused sets the focus state of the table.
+func WithFocused(f bool) Option {
+	return func(m *Model) {
+		m.focus = f
+	}
+}
+
+// WithStyles sets the table styles.
+func WithStyles(s Styles) Option {
+	return func(m *Model) {
+		m.styles = s
+	}
+}
+
+// WithKeyMap sets the key map.
+func WithKeyMap(km KeyMap) Option {
+	return func(m *Model) {
+		m.KeyMap = km
+	}
+}
+
+// Update is the Bubble Tea update loop.
+func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
+	if !m.focus {
+		return m, nil
+	}
+
+	var cmds []tea.Cmd
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch {
+		case key.Matches(msg, m.KeyMap.LineUp):
+			m.MoveUp(1)
+		case key.Matches(msg, m.KeyMap.LineDown):
+			m.MoveDown(1)
+		case key.Matches(msg, m.KeyMap.PageUp):
+			m.MoveUp(m.viewport.Height)
+		case key.Matches(msg, m.KeyMap.PageDown):
+			m.MoveDown(m.viewport.Height)
+		case key.Matches(msg, m.KeyMap.HalfPageUp):
+			m.MoveUp(m.viewport.Height / 2)
+		case key.Matches(msg, m.KeyMap.HalfPageDown):
+			m.MoveDown(m.viewport.Height / 2)
+		case key.Matches(msg, m.KeyMap.LineDown):
+			m.MoveDown(1)
+		case key.Matches(msg, m.KeyMap.GotoTop):
+			m.GotoTop()
+		case key.Matches(msg, m.KeyMap.GotoBottom):
+			m.GotoBottom()
+		}
+	}
+
+	return m, tea.Batch(cmds...)
+}
+
+// Focused returns the focus state of the table.
+func (m Model) Focused() bool {
+	return m.focus
+}
+
+// Focus focusses the table, allowing the user to move around the rows and
+// interact.
+func (m *Model) Focus() {
+	m.focus = true
+	m.UpdateViewport()
+}
+
+// Blur blurs the table, preventing selection or movement.
+func (m *Model) Blur() {
+	m.focus = false
+	m.UpdateViewport()
+}
+
+// View renders the component.
+func (m Model) View() string {
+	return m.headersView() + "\n" + m.viewport.View()
+}
+
+// UpdateViewport updates the list content based on the previously defined
+// columns and rows.
+func (m *Model) UpdateViewport() {
+	renderedRows := make([]string, 0, len(m.rows))
+	for i := range m.rows {
+		renderedRows = append(renderedRows, m.renderRow(i))
+	}
+
+	m.viewport.SetContent(
+		lipgloss.JoinVertical(lipgloss.Left, renderedRows...),
+	)
+}
+
+// SelectedRow returns the selected row.
+// You can cast it to your own implementation.
+func (m Model) SelectedRow() Row {
+	return m.rows[m.cursor]
+}
+
+// SetRows set a new rows state.
+func (m *Model) SetRows(r []Row) {
+	m.rows = r
+	m.UpdateViewport()
+}
+
+// SetWidth sets the width of the viewport of the table.
+func (m *Model) SetWidth(w int) {
+	m.viewport.Width = w
+	m.UpdateViewport()
+}
+
+// SetHeight sets the height of the viewport of the table.
+func (m *Model) SetHeight(h int) {
+	m.viewport.Height = h
+	m.UpdateViewport()
+}
+
+// Height returns the viewport height of the table.
+func (m Model) Height() int {
+	return m.viewport.Height
+}
+
+// Width returns the viewport width of the table.
+func (m Model) Width() int {
+	return m.viewport.Width
+}
+
+// Cursor returns the index of the selected row.
+func (m Model) Cursor() int {
+	return m.cursor
+}
+
+// SetCursor sets the cursor position in the table.
+func (m *Model) SetCursor(n int) {
+	m.cursor = clamp(n, 0, len(m.rows)-1)
+	m.UpdateViewport()
+}
+
+// MoveUp moves the selection up by any number of row.
+// It can not go above the first row.
+func (m *Model) MoveUp(n int) {
+	m.cursor = clamp(m.cursor-n, 0, len(m.rows)-1)
+	m.UpdateViewport()
+
+	if m.cursor < m.viewport.YOffset {
+		m.viewport.SetYOffset(m.cursor)
+	}
+}
+
+// MoveDown moves the selection down by any number of row.
+// It can not go below the last row.
+func (m *Model) MoveDown(n int) {
+	m.cursor = clamp(m.cursor+n, 0, len(m.rows)-1)
+	m.UpdateViewport()
+
+	if m.cursor > (m.viewport.YOffset + (m.viewport.Height - 1)) {
+		m.viewport.SetYOffset(m.cursor - (m.viewport.Height - 1))
+	}
+}
+
+// GotoTop moves the selection to the first row.
+func (m *Model) GotoTop() {
+	m.MoveUp(m.cursor)
+}
+
+// GotoBottom moves the selection to the last row.
+func (m *Model) GotoBottom() {
+	m.MoveDown(len(m.rows))
+}
+
+// FromValues create the table rows from a simple string. It uses `\n` by
+// default for getting all the rows and the given separator for the fields on
+// each row.
+func (m *Model) FromValues(value, separator string) {
+	rows := []Row{}
+	for _, line := range strings.Split(value, "\n") {
+		r := Row{}
+		for _, field := range strings.Split(line, separator) {
+			r = append(r, field)
+		}
+		rows = append(rows, r)
+	}
+
+	m.SetRows(rows)
+}
+
+func (m Model) headersView() string {
+	var s = make([]string, 0, len(m.cols))
+	for _, col := range m.cols {
+		style := lipgloss.NewStyle().Width(col.Width).MaxWidth(col.Width).Inline(true)
+		renderedCell := style.Render(runewidth.Truncate(col.Title, col.Width, "…"))
+		s = append(s, m.styles.Header.Render(renderedCell))
+	}
+	return lipgloss.JoinHorizontal(lipgloss.Left, s...)
+}
+
+func (m *Model) renderRow(rowID int) string {
+	var s = make([]string, 0, len(m.cols))
+	for i, value := range m.rows[rowID] {
+		style := lipgloss.NewStyle().Width(m.cols[i].Width).MaxWidth(m.cols[i].Width).Inline(true)
+		renderedCell := m.styles.Cell.Render(style.Render(runewidth.Truncate(value, m.cols[i].Width, "…")))
+		s = append(s, renderedCell)
+	}
+
+	row := lipgloss.JoinHorizontal(lipgloss.Left, s...)
+
+	if rowID == m.cursor {
+		return m.styles.Selected.Render(row)
+	}
+
+	return row
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+
+	return b
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+
+	return b
+}
+
+func clamp(v, low, high int) int {
+	return min(max(v, low), high)
+}

table/table_test.go

@@ -0,0 +1,54 @@
+package table
+
+import "testing"
+
+func TestFromValues(t *testing.T) {
+	input := "foo1,bar1\nfoo2,bar2\nfoo3,bar3"
+	table := New(WithColumns([]Column{{Title: "Foo"}, {Title: "Bar"}}))
+	table.FromValues(input, ",")
+
+	if len(table.rows) != 3 {
+		t.Fatalf("expect table to have 3 rows but it has %d", len(table.rows))
+	}
+
+	expect := []Row{
+		{"foo1", "bar1"},
+		{"foo2", "bar2"},
+		{"foo3", "bar3"},
+	}
+	if !deepEqual(table.rows, expect) {
+		t.Fatal("table rows is not equals to the input")
+	}
+}
+
+func TestFromValuesWithTabSeparator(t *testing.T) {
+	input := "foo1.\tbar1\nfoo,bar,baz\tbar,2"
+	table := New(WithColumns([]Column{{Title: "Foo"}, {Title: "Bar"}}))
+	table.FromValues(input, "\t")
+
+	if len(table.rows) != 2 {
+		t.Fatalf("expect table to have 2 rows but it has %d", len(table.rows))
+	}
+
+	expect := []Row{
+		{"foo1.", "bar1"},
+		{"foo,bar,baz", "bar,2"},
+	}
+	if !deepEqual(table.rows, expect) {
+		t.Fatal("table rows is not equals to the input")
+	}
+}
+
+func deepEqual(a, b []Row) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, r := range a {
+		for j, f := range r {
+			if f != b[i][j] {
+				return false
+			}
+		}
+	}
+	return true
+}

textarea/textarea_test.go

@@ -0,0 +1,446 @@
+package textarea
+
+import (
+	"strings"
+	"testing"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+func TestNew(t *testing.T) {
+	textarea := newTextArea()
+	view := textarea.View()
+
+	if !strings.Contains(view, ">") {
+		t.Log(view)
+		t.Error("Text area did not render the prompt")
+	}
+
+	if !strings.Contains(view, "World!") {
+		t.Log(view)
+		t.Error("Text area did not render the placeholder")
+	}
+}
+
+func TestInput(t *testing.T) {
+	textarea := newTextArea()
+
+	input := "foo"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+	}
+
+	view := textarea.View()
+
+	if !strings.Contains(view, input) {
+		t.Log(view)
+		t.Error("Text area did not render the input")
+	}
+
+	if textarea.col != len(input) {
+		t.Log(view)
+		t.Error("Text area did not move the cursor to the correct position")
+	}
+}
+
+func TestSoftWrap(t *testing.T) {
+	textarea := newTextArea()
+	textarea.Prompt = ""
+	textarea.ShowLineNumbers = false
+	textarea.SetWidth(5)
+	textarea.SetHeight(5)
+	textarea.CharLimit = 60
+
+	textarea, _ = textarea.Update(nil)
+
+	input := "foo bar baz"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+	}
+
+	view := textarea.View()
+
+	for _, word := range strings.Split(input, " ") {
+		if !strings.Contains(view, word) {
+			t.Log(view)
+			t.Error("Text area did not render the input")
+		}
+	}
+
+	// Due to the word wrapping, each word will be on a new line and the
+	// text area will look like this:
+	//
+	// > foo
+	// > bar
+	// > baz█
+	//
+	// However, due to soft-wrapping the column will still be at the end of the line.
+	if textarea.row != 0 || textarea.col != len(input) {
+		t.Log(view)
+		t.Error("Text area did not move the cursor to the correct position")
+	}
+}
+
+func TestCharLimit(t *testing.T) {
+	textarea := newTextArea()
+
+	// First input (foo bar) should be accepted as it will fall within the
+	// CharLimit. Second input (baz) should not appear in the input.
+	input := []string{"foo bar", "baz"}
+	textarea.CharLimit = len(input[0])
+
+	for _, k := range []rune(strings.Join(input, " ")) {
+		textarea, _ = textarea.Update(keyPress(k))
+	}
+
+	view := textarea.View()
+	if strings.Contains(view, input[1]) {
+		t.Log(view)
+		t.Error("Text area should not include input past the character limit")
+	}
+}
+
+func TestVerticalScrolling(t *testing.T) {
+	textarea := newTextArea()
+	textarea.Prompt = ""
+	textarea.ShowLineNumbers = false
+	textarea.SetHeight(1)
+	textarea.SetWidth(20)
+	textarea.CharLimit = 100
+
+	textarea, _ = textarea.Update(nil)
+
+	input := "This is a really long line that should wrap around the text area."
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+	}
+
+	view := textarea.View()
+
+	// The view should contain the first "line" of the input.
+	if !strings.Contains(view, "This is a really") {
+		t.Log(view)
+		t.Error("Text area did not render the input")
+	}
+
+	// But we should be able to scroll to see the next line.
+	// Let's scroll down for each line to view the full input.
+	lines := []string{
+		"long line that",
+		"should wrap around",
+		"the text area.",
+	}
+	for _, line := range lines {
+		textarea.viewport.LineDown(1)
+		view = textarea.View()
+		if !strings.Contains(view, line) {
+			t.Log(view)
+			t.Error("Text area did not render the correct scrolled input")
+		}
+	}
+}
+
+func TestWordWrapOverflowing(t *testing.T) {
+	// An interesting edge case is when the user enters many words that fill up
+	// the text area and then goes back up and inserts a few words which causes
+	// a cascading wrap and causes an overflow of the last line.
+	//
+	// In this case, we should not let the user insert more words if, after the
+	// entire wrap is complete, the last line is overflowing.
+	textarea := newTextArea()
+
+	textarea.SetHeight(3)
+	textarea.SetWidth(20)
+	textarea.CharLimit = 500
+
+	textarea, _ = textarea.Update(nil)
+
+	input := "Testing Testing Testing Testing Testing Testing Testing Testing"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+		textarea.View()
+	}
+
+	// We have essentially filled the text area with input.
+	// Let's see if we can cause wrapping to overflow the last line.
+	textarea.row = 0
+	textarea.col = 0
+
+	input = "Testing"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+		textarea.View()
+	}
+
+	lastLineWidth := textarea.LineInfo().Width
+	if lastLineWidth > 20 {
+		t.Log(lastLineWidth)
+		t.Log(textarea.View())
+		t.Fail()
+	}
+}
+
+func TestValueSoftWrap(t *testing.T) {
+	textarea := newTextArea()
+	textarea.SetWidth(16)
+	textarea.SetHeight(10)
+	textarea.CharLimit = 500
+
+	textarea, _ = textarea.Update(nil)
+
+	input := "Testing Testing Testing Testing Testing Testing Testing Testing"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+		textarea.View()
+	}
+
+	value := textarea.Value()
+	if value != input {
+		t.Log(value)
+		t.Log(input)
+		t.Fatal("The text area does not have the correct value")
+	}
+}
+
+func TestSetValue(t *testing.T) {
+	textarea := newTextArea()
+	textarea.SetValue(strings.Join([]string{"Foo", "Bar", "Baz"}, "\n"))
+
+	if textarea.row != 2 && textarea.col != 3 {
+		t.Log(textarea.row, textarea.col)
+		t.Fatal("Cursor Should be on row 2 column 3 after inserting 2 new lines")
+	}
+
+	value := textarea.Value()
+	if value != "Foo\nBar\nBaz" {
+		t.Fatal("Value should be Foo\nBar\nBaz")
+	}
+
+	// SetValue should reset text area
+	textarea.SetValue("Test")
+	value = textarea.Value()
+	if value != "Test" {
+		t.Log(value)
+		t.Fatal("Text area was not reset when SetValue() was called")
+	}
+}
+
+func TestInsertString(t *testing.T) {
+	textarea := newTextArea()
+
+	// Insert some text
+	input := "foo baz"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+	}
+
+	// Put cursor in the middle of the text
+	textarea.col = 4
+
+	textarea.InsertString("bar ")
+
+	value := textarea.Value()
+	if value != "foo bar baz" {
+		t.Log(value)
+		t.Fatal("Expected insert string to insert bar between foo and baz")
+	}
+}
+
+func TestCanHandleEmoji(t *testing.T) {
+	textarea := newTextArea()
+	input := "🧋"
+
+	for _, k := range []rune(input) {
+		textarea, _ = textarea.Update(keyPress(k))
+	}
+
+	value := textarea.Value()
+	if value != input {
+		t.Log(value)
+		t.Fatal("Expected emoji to be inserted")
+	}
+
+	input = "🧋🧋🧋"
+
+	textarea.SetValue(input)
+
+	value = textarea.Value()
+	if value != input {
+		t.Log(value)
+		t.Fatal("Expected emoji to be inserted")
+	}
+
+	if textarea.col != 3 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the third character")
+	}
+
+	if charOffset := textarea.LineInfo().CharOffset; charOffset != 6 {
+		t.Log(charOffset)
+		t.Fatal("Expected cursor to be on the sixth character")
+	}
+}
+
+func TestVerticalNavigationKeepsCursorHorizontalPosition(t *testing.T) {
+	textarea := newTextArea()
+	textarea.SetWidth(20)
+
+	textarea.SetValue(strings.Join([]string{"你好你好", "Hello"}, "\n"))
+
+	textarea.row = 0
+	textarea.col = 2
+
+	// 你好|你好
+	// Hell|o
+	// 1234|
+
+	// Let's imagine our cursor is on the first line where the pipe is.
+	// We press the down arrow to get to the next line.
+	// The issue is that if we keep the cursor on the same column, the cursor will jump to after the `e`.
+	//
+	// 你好|你好
+	// He|llo
+	//
+	// But this is wrong because visually we were at the 4th character due to
+	// the first line containing double-width runes.
+	// We want to keep the cursor on the same visual column.
+	//
+	// 你好|你好
+	// Hell|o
+	//
+	// This test ensures that the cursor is kept on the same visual column by
+	// ensuring that the column offset goes from 2 -> 4.
+
+	lineInfo := textarea.LineInfo()
+	if lineInfo.CharOffset != 4 || lineInfo.ColumnOffset != 2 {
+		t.Log(lineInfo.CharOffset)
+		t.Log(lineInfo.ColumnOffset)
+		t.Fatal("Expected cursor to be on the fourth character because there two double width runes on the first line.")
+	}
+
+	downMsg := tea.KeyMsg{Type: tea.KeyDown, Alt: false, Runes: []rune{}}
+	textarea, _ = textarea.Update(downMsg)
+
+	lineInfo = textarea.LineInfo()
+	if lineInfo.CharOffset != 4 || lineInfo.ColumnOffset != 4 {
+		t.Log(lineInfo.CharOffset)
+		t.Log(lineInfo.ColumnOffset)
+		t.Fatal("Expected cursor to be on the fourth character because we came down from the first line.")
+	}
+}
+
+func TestVerticalNavigationShouldRememberPositionWhileTraversing(t *testing.T) {
+	textarea := newTextArea()
+	textarea.SetWidth(40)
+
+	// Let's imagine we have a text area with the following content:
+	//
+	// Hello
+	// World
+	// This is a long line.
+	//
+	// If we are at the end of the last line and go up, we should be at the end
+	// of the second line.
+	// And, if we go up again we should be at the end of the first line.
+	// But, if we go back down twice, we should be at the end of the last line
+	// again and not the fifth (length of second line) character of the last line.
+	//
+	// In other words, we should remember the last horizontal position while
+	// traversing vertically.
+
+	textarea.SetValue(strings.Join([]string{"Hello", "World", "This is a long line."}, "\n"))
+
+	// We are at the end of the last line.
+	if textarea.col != 20 || textarea.row != 2 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the 20th character of the last line")
+	}
+
+	// Let's go up.
+	upMsg := tea.KeyMsg{Type: tea.KeyUp, Alt: false, Runes: []rune{}}
+	textarea, _ = textarea.Update(upMsg)
+
+	// We should be at the end of the second line.
+	if textarea.col != 5 || textarea.row != 1 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the 5th character of the second line")
+	}
+
+	// And, again.
+	textarea, _ = textarea.Update(upMsg)
+
+	// We should be at the end of the first line.
+	if textarea.col != 5 || textarea.row != 0 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the 5th character of the first line")
+	}
+
+	// Let's go down, twice.
+	downMsg := tea.KeyMsg{Type: tea.KeyDown, Alt: false, Runes: []rune{}}
+	textarea, _ = textarea.Update(downMsg)
+	textarea, _ = textarea.Update(downMsg)
+
+	// We should be at the end of the last line.
+	if textarea.col != 20 || textarea.row != 2 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the 20th character of the last line")
+	}
+
+	// Now, for correct behavior, if we move right or left, we should forget
+	// (reset) the saved horizontal position. Since we assume the user wants to
+	// keep the cursor where it is horizontally. This is how most text areas
+	// work.
+
+	textarea, _ = textarea.Update(upMsg)
+	leftMsg := tea.KeyMsg{Type: tea.KeyLeft, Alt: false, Runes: []rune{}}
+	textarea, _ = textarea.Update(leftMsg)
+
+	if textarea.col != 4 || textarea.row != 1 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the 5th character of the second line")
+	}
+
+	// Going down now should keep us at the 4th column since we moved left and
+	// reset the horizontal position saved state.
+	textarea, _ = textarea.Update(downMsg)
+	if textarea.col != 4 || textarea.row != 2 {
+		t.Log(textarea.col)
+		t.Fatal("Expected cursor to be on the 4th character of the last line")
+	}
+}
+
+func TestRendersEndOfLineBuffer(t *testing.T) {
+	textarea := newTextArea()
+	textarea.ShowLineNumbers = true
+	textarea.SetWidth(20)
+
+	view := textarea.View()
+	if !strings.Contains(view, "~") {
+		t.Log(view)
+		t.Fatal("Expected to see a tilde at the end of the line")
+	}
+}
+
+func newTextArea() Model {
+	textarea := New()
+
+	textarea.Prompt = "> "
+	textarea.Placeholder = "Hello, World!"
+
+	textarea.Focus()
+
+	textarea, _ = textarea.Update(nil)
+
+	return textarea
+}
+
+func keyPress(key rune) tea.Msg {
+	return tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{key}, Alt: false}
+}

textinput/textinput.go

@@ -1,24 +1,19 @@
 package textinput
 
 import (
-	"context"
 	"strings"
 	"time"
 	"unicode"
 
 	"github.com/atotto/clipboard"
+	"github.com/charmbracelet/bubbles/cursor"
+	"github.com/charmbracelet/bubbles/key"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 	rw "github.com/mattn/go-runewidth"
 )
 
-const defaultBlinkSpeed = time.Millisecond * 530
-
-// blinkMsg and blinkCanceled are used to manage cursor blinking.
-type blinkMsg struct{}
-type blinkCanceled struct{}
-
-// Messages for clipboard events.
+// Internal messages for clipboard operations.
 type pasteMsg string
 type pasteErrMsg struct{ error }
 
@@ -37,22 +32,46 @@ const (
 	// seen for password fields on the command line.
 	EchoNone
 
-	// EchoOnEdit
+	// EchoOnEdit.
 )
 
-// blinkCtx manages cursor blinking.
-type blinkCtx struct {
-	ctx    context.Context
-	cancel context.CancelFunc
+// ValidateFunc is a function that returns an error if the input is invalid.
+type ValidateFunc func(string) error
+
+// KeyMap is the key bindings for different actions within the textinput.
+type KeyMap struct {
+	CharacterForward        key.Binding
+	CharacterBackward       key.Binding
+	WordForward             key.Binding
+	WordBackward            key.Binding
+	DeleteWordBackward      key.Binding
+	DeleteWordForward       key.Binding
+	DeleteAfterCursor       key.Binding
+	DeleteBeforeCursor      key.Binding
+	DeleteCharacterBackward key.Binding
+	DeleteCharacterForward  key.Binding
+	LineStart               key.Binding
+	LineEnd                 key.Binding
+	Paste                   key.Binding
 }
 
-type cursorMode int
-
-const (
-	cursorBlink = iota
-	cursorStatic
-	cursorHide
-)
+// DefaultKeyMap is the default set of key bindings for navigating and acting
+// upon the textinput.
+var DefaultKeyMap = KeyMap{
+	CharacterForward:        key.NewBinding(key.WithKeys("right", "ctrl+f")),
+	CharacterBackward:       key.NewBinding(key.WithKeys("left", "ctrl+b")),
+	WordForward:             key.NewBinding(key.WithKeys("alt+right", "alt+f")),
+	WordBackward:            key.NewBinding(key.WithKeys("alt+left", "alt+b")),
+	DeleteWordBackward:      key.NewBinding(key.WithKeys("alt+backspace", "ctrl+w")),
+	DeleteWordForward:       key.NewBinding(key.WithKeys("alte+delete", "alt+d")),
+	DeleteAfterCursor:       key.NewBinding(key.WithKeys("ctrl+k")),
+	DeleteBeforeCursor:      key.NewBinding(key.WithKeys("ctrl+u")),
+	DeleteCharacterBackward: key.NewBinding(key.WithKeys("backspace", "ctrl+h")),
+	DeleteCharacterForward:  key.NewBinding(key.WithKeys("delete", "ctrl+d")),
+	LineStart:               key.NewBinding(key.WithKeys("home", "ctrl+a")),
+	LineEnd:                 key.NewBinding(key.WithKeys("end", "ctrl+e")),
+	Paste:                   key.NewBinding(key.WithKeys("ctrl+v")),
+}
 
 // Model is the Bubble Tea model for this text input element.
 type Model struct {
@@ -61,10 +80,13 @@ type Model struct {
 	// General settings.
 	Prompt        string
 	Placeholder   string
-	Cursor        string
-	BlinkSpeed    time.Duration
 	EchoMode      EchoMode
 	EchoCharacter rune
+	Cursor        cursor.Model
+
+	// Deprecated: use cursor.BlinkSpeed instead.
+	// This is unused and will be removed in the future.
+	BlinkSpeed time.Duration
 
 	// Styles. These will be applied as inline styles.
 	//
@@ -85,16 +107,16 @@ type Model struct {
 	// viewport. If 0 or less this setting is ignored.
 	Width int
 
+	// KeyMap encodes the keybindings recognized by the widget.
+	KeyMap KeyMap
+
 	// Underlying text value.
 	value []rune
 
-	// Focus indicates whether user input focus should be on this input
-	// component. When false, don't blink and ignore keyboard input.
+	// focus indicates whether user input focus should be on this input
+	// component. When false, ignore keyboard input and hide the cursor.
 	focus bool
 
-	// Cursor blink state.
-	blink bool
-
 	// Cursor position.
 	pos int
 
@@ -103,43 +125,53 @@ type Model struct {
 	offset      int
 	offsetRight int
 
-	// Used to manage cursor blink
-	blinkCtx *blinkCtx
-
-	// cursorMode determines the behavior of the cursor
-	cursorMode cursorMode
+	// Validate is a function that checks whether or not the text within the
+	// input is valid. If it is not valid, the `Err` field will be set to the
+	// error returned by the function. If the function is not defined, all
+	// input is considered valid.
+	Validate ValidateFunc
 }
 
-// NewModel creates a new model with default settings.
-func NewModel() Model {
+// New creates a new model with default settings.
+func New() Model {
 	return Model{
 		Prompt:           "> ",
-		BlinkSpeed:       defaultBlinkSpeed,
 		EchoCharacter:    '*',
 		CharLimit:        0,
 		PlaceholderStyle: lipgloss.NewStyle().Foreground(lipgloss.Color("240")),
+		Cursor:           cursor.New(),
+		KeyMap:           DefaultKeyMap,
 
-		value:      nil,
-		focus:      false,
-		blink:      true,
-		pos:        0,
-		cursorMode: cursorBlink,
-
-		blinkCtx: &blinkCtx{
-			ctx: context.Background(),
-		},
+		value: nil,
+		focus: false,
+		pos:   0,
 	}
 }
 
+// NewModel creates a new model with default settings.
+//
+// Deprecated. Use New instead.
+var NewModel = New
+
 // SetValue sets the value of the text input.
 func (m *Model) SetValue(s string) {
+	if m.Validate != nil {
+		if err := m.Validate(s); err != nil {
+			m.Err = err
+			return
+		}
+	}
+
+	empty := len(m.value) == 0
+	m.Err = nil
+
 	runes := []rune(s)
 	if m.CharLimit > 0 && len(runes) > m.CharLimit {
 		m.value = runes[:m.CharLimit]
 	} else {
 		m.value = runes
 	}
-	if m.pos == 0 || m.pos > len(m.value) {
+	if (m.pos == 0 && empty) || m.pos > len(m.value) {
 		m.SetCursor(len(m.value))
 	}
 	m.handleOverflow()
@@ -150,30 +182,26 @@ func (m Model) Value() string {
 	return string(m.value)
 }
 
-// SetCursor start moves the cursor to the given position. If the position is
+// Position returns the cursor position.
+func (m Model) Position() int {
+	return m.pos
+}
+
+// SetCursor moves the cursor to the given position. If the position is
 // out of bounds the cursor will be moved to the start or end accordingly.
-// Returns whether or nor the cursor timer should be reset.
-func (m *Model) SetCursor(pos int) bool {
+func (m *Model) SetCursor(pos int) {
 	m.pos = clamp(pos, 0, len(m.value))
 	m.handleOverflow()
-
-	// Show the cursor unless it's been explicitly hidden
-	m.blink = m.cursorMode == cursorHide
-
-	// Reset cursor blink if necessary
-	return m.cursorMode == cursorBlink
 }
 
-// CursorStart moves the cursor to the start of the field. Returns whether or
-// not the curosr blink should be reset.
-func (m *Model) CursorStart() bool {
-	return m.SetCursor(0)
+// CursorStart moves the cursor to the start of the input field.
+func (m *Model) CursorStart() {
+	m.SetCursor(0)
 }
 
-// CursorEnd moves the cursor to the end of the field. Returns whether or not
-// the cursor blink should be reset.
-func (m *Model) CursorEnd() bool {
-	return m.SetCursor(len(m.value))
+// CursorEnd moves the cursor to the end of the input field.
+func (m *Model) CursorEnd() {
+	m.SetCursor(len(m.value))
 }
 
 // Focused returns the focus state on the model.
@@ -181,28 +209,28 @@ func (m Model) Focused() bool {
 	return m.focus
 }
 
-// Focus sets the focus state on the model.
-func (m *Model) Focus() {
+// Focus sets the focus state on the model. When the model is in focus it can
+// receive keyboard input and the cursor will be shown.
+func (m *Model) Focus() tea.Cmd {
 	m.focus = true
-	m.blink = m.cursorMode == cursorHide // show the cursor unless we've explicitly hidden it
+	return m.Cursor.Focus()
 }
 
-// Blur removes the focus state on the model.
+// Blur removes the focus state on the model.  When the model is blurred it can
+// not receive keyboard input and the cursor will be hidden.
 func (m *Model) Blur() {
 	m.focus = false
-	m.blink = true
+	m.Cursor.Blur()
 }
 
-// Reset sets the input to its default state with no input. Returns whether
-// or not the cursor blink should reset.
-func (m *Model) Reset() bool {
+// Reset sets the input to its default state with no input.
+func (m *Model) Reset() {
 	m.value = nil
-	return m.SetCursor(0)
+	m.SetCursor(0)
 }
 
-// handle a clipboard paste event, if supported. Returns whether or not the
-// cursor blink should be reset.
-func (m *Model) handlePaste(v string) bool {
+// handle a clipboard paste event, if supported.
+func (m *Model) handlePaste(v string) {
 	paste := []rune(v)
 
 	var availSpace int
@@ -212,7 +240,7 @@ func (m *Model) handlePaste(v string) bool {
 
 	// If the char limit's been reached cancel
 	if m.CharLimit > 0 && availSpace <= 0 {
-		return false
+		return
 	}
 
 	// If there's not enough space to paste the whole thing cut the pasted
@@ -227,6 +255,8 @@ func (m *Model) handlePaste(v string) bool {
 	tail := make([]rune, len(tailSrc))
 	copy(tail, tailSrc)
 
+	oldPos := m.pos
+
 	// Insert pasted runes
 	for _, r := range paste {
 		head = append(head, r)
@@ -240,10 +270,14 @@ func (m *Model) handlePaste(v string) bool {
 	}
 
 	// Put it all back together
-	m.value = append(head, tail...)
+	value := append(head, tail...)
+	m.SetValue(string(value))
 
-	// Reset blink state if necessary and run overflow checks
-	return m.SetCursor(m.pos)
+	if m.Err != nil {
+		m.pos = oldPos
+	}
+
+	m.SetCursor(m.pos)
 }
 
 // If a max width is defined, perform some logic to treat the visible area
@@ -291,53 +325,87 @@ func (m *Model) handleOverflow() {
 	}
 }
 
-// deleteWordLeft deletes the word left to the cursor. Returns whether or not
-// the cursor blink should be reset.
-func (m *Model) deleteWordLeft() bool {
+// deleteBeforeCursor deletes all text before the cursor.
+func (m *Model) deleteBeforeCursor() {
+	m.value = m.value[m.pos:]
+	m.offset = 0
+	m.SetCursor(0)
+}
+
+// deleteAfterCursor deletes all text after the cursor. If input is masked
+// delete everything after the cursor so as not to reveal word breaks in the
+// masked input.
+func (m *Model) deleteAfterCursor() {
+	m.value = m.value[:m.pos]
+	m.SetCursor(len(m.value))
+}
+
+// deleteWordBackward deletes the word left to the cursor.
+func (m *Model) deleteWordBackward() {
 	if m.pos == 0 || len(m.value) == 0 {
-		return false
+		return
 	}
 
-	i := m.pos
-	blink := m.SetCursor(m.pos - 1)
+	if m.EchoMode != EchoNormal {
+		m.deleteBeforeCursor()
+		return
+	}
+
+	// Linter note: it's critical that we acquire the initial cursor position
+	// here prior to altering it via SetCursor() below. As such, moving this
+	// call into the corresponding if clause does not apply here.
+	oldPos := m.pos //nolint:ifshort
+
+	m.SetCursor(m.pos - 1)
 	for unicode.IsSpace(m.value[m.pos]) {
+		if m.pos <= 0 {
+			break
+		}
 		// ignore series of whitespace before cursor
-		blink = m.SetCursor(m.pos - 1)
+		m.SetCursor(m.pos - 1)
 	}
 
 	for m.pos > 0 {
 		if !unicode.IsSpace(m.value[m.pos]) {
-			blink = m.SetCursor(m.pos - 1)
+			m.SetCursor(m.pos - 1)
 		} else {
 			if m.pos > 0 {
 				// keep the previous space
-				blink = m.SetCursor(m.pos + 1)
+				m.SetCursor(m.pos + 1)
 			}
 			break
 		}
 	}
 
-	if i > len(m.value) {
+	if oldPos > len(m.value) {
 		m.value = m.value[:m.pos]
 	} else {
-		m.value = append(m.value[:m.pos], m.value[i:]...)
+		m.value = append(m.value[:m.pos], m.value[oldPos:]...)
 	}
-
-	return blink
 }
 
-// deleteWordRight deletes the word right to the cursor. Returns whether or not
-// the cursor blink should be reset.
-func (m *Model) deleteWordRight() bool {
+// deleteWordForward deletes the word right to the cursor If input is masked
+// delete everything after the cursor so as not to reveal word breaks in the
+// masked input.
+func (m *Model) deleteWordForward() {
 	if m.pos >= len(m.value) || len(m.value) == 0 {
-		return false
+		return
 	}
 
-	i := m.pos
+	if m.EchoMode != EchoNormal {
+		m.deleteAfterCursor()
+		return
+	}
+
+	oldPos := m.pos
 	m.SetCursor(m.pos + 1)
 	for unicode.IsSpace(m.value[m.pos]) {
 		// ignore series of whitespace after cursor
 		m.SetCursor(m.pos + 1)
+
+		if m.pos >= len(m.value) {
+			break
+		}
 	}
 
 	for m.pos < len(m.value) {
@@ -349,26 +417,30 @@ func (m *Model) deleteWordRight() bool {
 	}
 
 	if m.pos > len(m.value) {
-		m.value = m.value[:i]
+		m.value = m.value[:oldPos]
 	} else {
-		m.value = append(m.value[:i], m.value[m.pos:]...)
+		m.value = append(m.value[:oldPos], m.value[m.pos:]...)
 	}
 
-	return m.SetCursor(i)
+	m.SetCursor(oldPos)
 }
 
-// wordLeft moves the cursor one word to the left. Returns whether or not the
-// cursor blink should be reset.
-func (m *Model) wordLeft() bool {
+// wordBackward moves the cursor one word to the left. If input is masked, move
+// input to the start so as not to reveal word breaks in the masked input.
+func (m *Model) wordBackward() {
 	if m.pos == 0 || len(m.value) == 0 {
-		return false
+		return
+	}
+
+	if m.EchoMode != EchoNormal {
+		m.CursorStart()
+		return
 	}
 
-	blink := false
 	i := m.pos - 1
 	for i >= 0 {
 		if unicode.IsSpace(m.value[i]) {
-			blink = m.SetCursor(m.pos - 1)
+			m.SetCursor(m.pos - 1)
 			i--
 		} else {
 			break
@@ -377,28 +449,30 @@ func (m *Model) wordLeft() bool {
 
 	for i >= 0 {
 		if !unicode.IsSpace(m.value[i]) {
-			blink = m.SetCursor(m.pos - 1)
+			m.SetCursor(m.pos - 1)
 			i--
 		} else {
 			break
 		}
 	}
-
-	return blink
 }
 
-// wordRight moves the cursor one word to the right. Returns whether or not the
-// cursor blink should be reset.
-func (m *Model) wordRight() bool {
+// wordForward moves the cursor one word to the right. If the input is masked,
+// move input to the end so as not to reveal word breaks in the masked input.
+func (m *Model) wordForward() {
 	if m.pos >= len(m.value) || len(m.value) == 0 {
-		return false
+		return
+	}
+
+	if m.EchoMode != EchoNormal {
+		m.CursorEnd()
+		return
 	}
 
-	blink := false
 	i := m.pos
 	for i < len(m.value) {
 		if unicode.IsSpace(m.value[i]) {
-			blink = m.SetCursor(m.pos + 1)
+			m.SetCursor(m.pos + 1)
 			i++
 		} else {
 			break
@@ -407,14 +481,12 @@ func (m *Model) wordRight() bool {
 
 	for i < len(m.value) {
 		if !unicode.IsSpace(m.value[i]) {
-			blink = m.SetCursor(m.pos + 1)
+			m.SetCursor(m.pos + 1)
 			i++
 		} else {
 			break
 		}
 	}
-
-	return blink
 }
 
 func (m Model) echoTransform(v string) string {
@@ -432,109 +504,92 @@ func (m Model) echoTransform(v string) string {
 // Update is the Bubble Tea update loop.
 func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 	if !m.focus {
-		m.blink = true
 		return m, nil
 	}
 
-	var resetBlink bool
+	// Let's remember where the position of the cursor currently is so that if
+	// the cursor position changes, we can reset the blink.
+	oldPos := m.pos //nolint
 
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
-		switch msg.Type {
-		case tea.KeyBackspace: // delete character before cursor
-			if msg.Alt {
-				resetBlink = m.deleteWordLeft()
-			} else {
-				if len(m.value) > 0 {
-					m.value = append(m.value[:max(0, m.pos-1)], m.value[m.pos:]...)
-					if m.pos > 0 {
-						resetBlink = m.SetCursor(m.pos - 1)
-					}
+		switch {
+		case key.Matches(msg, m.KeyMap.DeleteWordBackward):
+			m.Err = nil
+			m.deleteWordBackward()
+		case key.Matches(msg, m.KeyMap.DeleteCharacterBackward):
+			m.Err = nil
+			if len(m.value) > 0 {
+				m.value = append(m.value[:max(0, m.pos-1)], m.value[m.pos:]...)
+				if m.pos > 0 {
+					m.SetCursor(m.pos - 1)
 				}
 			}
-		case tea.KeyLeft, tea.KeyCtrlB:
-			if msg.Alt { // alt+left arrow, back one word
-				resetBlink = m.wordLeft()
-				break
+		case key.Matches(msg, m.KeyMap.WordBackward):
+			m.wordBackward()
+		case key.Matches(msg, m.KeyMap.CharacterBackward):
+			if m.pos > 0 {
+				m.SetCursor(m.pos - 1)
 			}
-			if m.pos > 0 { // left arrow, ^F, back one character
-				resetBlink = m.SetCursor(m.pos - 1)
+		case key.Matches(msg, m.KeyMap.WordForward):
+			m.wordForward()
+		case key.Matches(msg, m.KeyMap.CharacterForward):
+			if m.pos < len(m.value) {
+				m.SetCursor(m.pos + 1)
 			}
-		case tea.KeyRight, tea.KeyCtrlF:
-			if msg.Alt { // alt+right arrow, forward one word
-				resetBlink = m.wordRight()
-				break
-			}
-			if m.pos < len(m.value) { // right arrow, ^F, forward one word
-				resetBlink = m.SetCursor(m.pos + 1)
-			}
-		case tea.KeyCtrlW: // ^W, delete word left of cursor
-			resetBlink = m.deleteWordLeft()
-		case tea.KeyHome, tea.KeyCtrlA: // ^A, go to beginning
-			resetBlink = m.CursorStart()
-		case tea.KeyDelete, tea.KeyCtrlD: // ^D, delete char under cursor
+		case key.Matches(msg, m.KeyMap.DeleteWordBackward):
+			m.deleteWordBackward()
+		case key.Matches(msg, m.KeyMap.LineStart):
+			m.CursorStart()
+		case key.Matches(msg, m.KeyMap.DeleteCharacterForward):
 			if len(m.value) > 0 && m.pos < len(m.value) {
 				m.value = append(m.value[:m.pos], m.value[m.pos+1:]...)
 			}
-		case tea.KeyCtrlE, tea.KeyEnd: // ^E, go to end
-			resetBlink = m.CursorEnd()
-		case tea.KeyCtrlK: // ^K, kill text after cursor
-			m.value = m.value[:m.pos]
-			resetBlink = m.SetCursor(len(m.value))
-		case tea.KeyCtrlU: // ^U, kill text before cursor
-			m.value = m.value[m.pos:]
-			resetBlink = m.SetCursor(0)
-			m.offset = 0
-		case tea.KeyCtrlV: // ^V paste
+		case key.Matches(msg, m.KeyMap.LineEnd):
+			m.CursorEnd()
+		case key.Matches(msg, m.KeyMap.DeleteAfterCursor):
+			m.deleteAfterCursor()
+		case key.Matches(msg, m.KeyMap.DeleteBeforeCursor):
+			m.deleteBeforeCursor()
+		case key.Matches(msg, m.KeyMap.Paste):
 			return m, Paste
-		case tea.KeyRunes: // input regular characters
-			if msg.Alt && len(msg.Runes) == 1 {
-				if msg.Runes[0] == 'd' { // alt+d, delete word right of cursor
-					resetBlink = m.deleteWordRight()
-					break
-				}
-				if msg.Runes[0] == 'b' { // alt+b, back one word
-					resetBlink = m.wordLeft()
-					break
-				}
-				if msg.Runes[0] == 'f' { // alt+f, forward one word
-					resetBlink = m.wordRight()
-					break
-				}
-			}
-
+		case key.Matches(msg, m.KeyMap.DeleteWordForward):
+			m.deleteWordForward()
+		default:
 			// Input a regular character
 			if m.CharLimit <= 0 || len(m.value) < m.CharLimit {
-				m.value = append(m.value[:m.pos], append(msg.Runes, m.value[m.pos:]...)...)
-				resetBlink = m.SetCursor(m.pos + len(msg.Runes))
+				runes := msg.Runes
+
+				value := make([]rune, len(m.value))
+				copy(value, m.value)
+				value = append(value[:m.pos], append(runes, value[m.pos:]...)...)
+				m.SetValue(string(value))
+				if m.Err == nil {
+					m.SetCursor(m.pos + len(runes))
+				}
 			}
 		}
 
-	case blinkMsg:
-		var cmd tea.Cmd
-		if m.cursorMode == cursorBlink {
-			m.blink = !m.blink
-			cmd = m.blinkCmd()
-		}
-		return m, cmd
-
-	case blinkCanceled: // no-op
-		return m, nil
-
 	case pasteMsg:
-		resetBlink = m.handlePaste(string(msg))
+		m.handlePaste(string(msg))
 
 	case pasteErrMsg:
 		m.Err = msg
 	}
 
+	var cmds []tea.Cmd
 	var cmd tea.Cmd
-	if resetBlink {
-		cmd = m.blinkCmd()
+
+	m.Cursor, cmd = m.Cursor.Update(msg)
+	cmds = append(cmds, cmd)
+
+	if oldPos != m.pos {
+		m.Cursor.Blink = false
+		cmds = append(cmds, m.Cursor.BlinkCmd())
 	}
 
 	m.handleOverflow()
-	return m, cmd
+	return m, tea.Batch(cmds...)
 }
 
 // View renders the textinput in its current state.
@@ -551,10 +606,13 @@ func (m Model) View() string {
 	v := styleText(m.echoTransform(string(value[:pos])))
 
 	if pos < len(value) {
-		v += m.cursorView(m.echoTransform(string(value[pos]))) // cursor and text under it
+		char := m.echoTransform(string(value[pos]))
+		m.Cursor.SetChar(char)
+		v += m.Cursor.View()                                   // cursor and text under it
 		v += styleText(m.echoTransform(string(value[pos+1:]))) // text after cursor
 	} else {
-		v += m.cursorView(" ")
+		m.Cursor.SetChar(" ")
+		v += m.Cursor.View()
 	}
 
 	// If a max width and background color were set fill the empty spaces with
@@ -579,12 +637,9 @@ func (m Model) placeholderView() string {
 		style = m.PlaceholderStyle.Inline(true).Render
 	)
 
-	// Cursor
-	if m.blink {
-		v += m.cursorView(style(p[:1]))
-	} else {
-		v += m.cursorView(p[:1])
-	}
+	m.Cursor.TextStyle = m.PlaceholderStyle
+	m.Cursor.SetChar(p[:1])
+	v += m.Cursor.View()
 
 	// The rest of the placeholder text
 	v += style(p[1:])
@@ -592,36 +647,9 @@ func (m Model) placeholderView() string {
 	return m.PromptStyle.Render(m.Prompt) + v
 }
 
-// cursorView styles the cursor.
-func (m Model) cursorView(v string) string {
-	if m.blink {
-		return m.TextStyle.Render(v)
-	}
-	return m.CursorStyle.Inline(true).Reverse(true).Render(v)
-}
-
-// blinkCmd is an internal command used to manage cursor blinking.
-func (m Model) blinkCmd() tea.Cmd {
-	if m.blinkCtx != nil && m.blinkCtx.cancel != nil {
-		m.blinkCtx.cancel()
-	}
-
-	ctx, cancel := context.WithTimeout(m.blinkCtx.ctx, m.BlinkSpeed)
-	m.blinkCtx.cancel = cancel
-
-	return func() tea.Msg {
-		defer cancel()
-		<-ctx.Done()
-		if ctx.Err() == context.DeadlineExceeded {
-			return blinkMsg{}
-		}
-		return blinkCanceled{}
-	}
-}
-
 // Blink is a command used to initialize cursor blinking.
 func Blink() tea.Msg {
-	return blinkMsg{}
+	return cursor.Blink()
 }
 
 // Paste is a command for pasting from the clipboard into the text input.
@@ -634,6 +662,9 @@ func Paste() tea.Msg {
 }
 
 func clamp(v, low, high int) int {
+	if high < low {
+		low, high = high, low
+	}
 	return min(high, max(low, v))
 }
 
@@ -650,3 +681,31 @@ func max(a, b int) int {
 	}
 	return b
 }
+
+// Deprecated.
+
+// Deprecated: use cursor.Mode.
+type CursorMode int
+
+const (
+	// Deprecated: use cursor.CursorBlink.
+	CursorBlink = CursorMode(cursor.CursorBlink)
+	// Deprecated: use cursor.CursorStatic.
+	CursorStatic = CursorMode(cursor.CursorStatic)
+	// Deprecated: use cursor.CursorHide.
+	CursorHide = CursorMode(cursor.CursorHide)
+)
+
+func (c CursorMode) String() string {
+	return cursor.Mode(c).String()
+}
+
+// Deprecated: use cursor.Mode().
+func (m Model) CursorMode() CursorMode {
+	return CursorMode(m.Cursor.Mode())
+}
+
+// Deprecated: use cursor.SetMode().
+func (m *Model) SetCursorMode(mode CursorMode) tea.Cmd {
+	return m.Cursor.SetMode(cursor.Mode(mode))
+}

timer/timer.go

@@ -0,0 +1,192 @@
+// Package timer provides a simple timeout component.
+package timer
+
+import (
+	"sync"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+var (
+	lastID int
+	idMtx  sync.Mutex
+)
+
+func nextID() int {
+	idMtx.Lock()
+	defer idMtx.Unlock()
+	lastID++
+	return lastID
+}
+
+// Authors note with regard to start and stop commands:
+//
+// Technically speaking, sending commands to start and stop the timer in this
+// case is extraneous. To stop the timer we'd just need to set the 'running'
+// property on the model to false which cause logic in the update function to
+// stop responding to TickMsgs. To start the model we'd set 'running' to true
+// and fire off a TickMsg. Helper functions would look like:
+//
+//     func (m *model) Start() tea.Cmd
+//     func (m *model) Stop()
+//
+// The danger with this approach, however, is that order of operations becomes
+// important with helper functions like the above. Consider the following:
+//
+//     // Would not work
+//     return m, m.timer.Start()
+//
+//	   // Would work
+//     cmd := m.timer.start()
+//     return m, cmd
+//
+// Thus, because of potential pitfalls like the ones above, we've introduced
+// the extraneous StartStopMsg to simplify the mental model when using this
+// package. Bear in mind that the practice of sending commands to simply
+// communicate with other parts of your application, such as in this package,
+// is still not recommended.
+
+// StartStopMsg is used to start and stop the timer.
+type StartStopMsg struct {
+	ID      int
+	running bool
+}
+
+// TickMsg is a message that is sent on every timer tick.
+type TickMsg struct {
+	// ID is the identifier of the stopwatch that send the message. This makes
+	// it possible to determine which timer a tick belongs to when there
+	// are multiple timers running.
+	//
+	// Note, however, that a timer will reject ticks from other stopwatches, so
+	// it's safe to flow all TickMsgs through all timers and have them still
+	// behave appropriately.
+	ID int
+
+	// Timeout returns whether or not this tick is a timeout tick. You can
+	// alternatively listen for TimeoutMsg.
+	Timeout bool
+}
+
+// TimeoutMsg is a message that is sent once when the timer times out.
+//
+// It's a convenience message sent alongside a TickMsg with the Timeout value
+// set to true.
+type TimeoutMsg struct {
+	ID int
+}
+
+// Model of the timer component.
+type Model struct {
+	// How long until the timer expires.
+	Timeout time.Duration
+
+	// How long to wait before every tick. Defaults to 1 second.
+	Interval time.Duration
+
+	id      int
+	running bool
+}
+
+// NewWithInterval creates a new timer with the given timeout and tick interval.
+func NewWithInterval(timeout, interval time.Duration) Model {
+	return Model{
+		Timeout:  timeout,
+		Interval: interval,
+		running:  true,
+		id:       nextID(),
+	}
+}
+
+// New creates a new timer with the given timeout and default 1s interval.
+func New(timeout time.Duration) Model {
+	return NewWithInterval(timeout, time.Second)
+}
+
+// ID returns the model's identifier. This can be used to determine if messages
+// belong to this timer instance when there are multiple timers.
+func (m Model) ID() int {
+	return m.id
+}
+
+// Running returns whether or not the timer is running. If the timer has timed
+// out this will always return false.
+func (m Model) Running() bool {
+	if m.Timedout() || !m.running {
+		return false
+	}
+	return true
+}
+
+// Timedout returns whether or not the timer has timed out.
+func (m Model) Timedout() bool {
+	return m.Timeout <= 0
+}
+
+// Init starts the timer.
+func (m Model) Init() tea.Cmd {
+	return m.tick()
+}
+
+// Update handles the timer tick.
+func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case StartStopMsg:
+		if msg.ID != 0 && msg.ID != m.id {
+			return m, nil
+		}
+		m.running = msg.running
+		return m, m.tick()
+	case TickMsg:
+		if !m.Running() || (msg.ID != 0 && msg.ID != m.id) {
+			break
+		}
+
+		m.Timeout -= m.Interval
+		return m, tea.Batch(m.tick(), m.timedout())
+	}
+
+	return m, nil
+}
+
+// View of the timer component.
+func (m Model) View() string {
+	return m.Timeout.String()
+}
+
+// Start resumes the timer. Has no effect if the timer has timed out.
+func (m *Model) Start() tea.Cmd {
+	return m.startStop(true)
+}
+
+// Stop pauses the timer. Has no effect if the timer has timed out.
+func (m *Model) Stop() tea.Cmd {
+	return m.startStop(false)
+}
+
+// Toggle stops the timer if it's running and starts it if it's stopped.
+func (m *Model) Toggle() tea.Cmd {
+	return m.startStop(!m.Running())
+}
+
+func (m Model) tick() tea.Cmd {
+	return tea.Tick(m.Interval, func(_ time.Time) tea.Msg {
+		return TickMsg{ID: m.id, Timeout: m.Timedout()}
+	})
+}
+
+func (m Model) timedout() tea.Cmd {
+	if !m.Timedout() {
+		return nil
+	}
+	return func() tea.Msg {
+		return TimeoutMsg{ID: m.id}
+	}
+}
+
+func (m Model) startStop(v bool) tea.Cmd {
+	return func() tea.Msg {
+		return StartStopMsg{ID: m.id, running: v}
+	}
+}

viewport/keymap.go

@@ -0,0 +1,48 @@
+package viewport
+
+import "github.com/charmbracelet/bubbles/key"
+
+const spacebar = " "
+
+// KeyMap defines the keybindings for the viewport. Note that you don't
+// necessary need to use keybindings at all; the viewport can be controlled
+// programmatically with methods like Model.LineDown(1). See the GoDocs for
+// details.
+type KeyMap struct {
+	PageDown     key.Binding
+	PageUp       key.Binding
+	HalfPageUp   key.Binding
+	HalfPageDown key.Binding
+	Down         key.Binding
+	Up           key.Binding
+}
+
+// DefaultKeyMap returns a set of pager-like default keybindings.
+func DefaultKeyMap() KeyMap {
+	return KeyMap{
+		PageDown: key.NewBinding(
+			key.WithKeys("pgdown", spacebar, "f"),
+			key.WithHelp("f/pgdn", "page down"),
+		),
+		PageUp: key.NewBinding(
+			key.WithKeys("pgup", "b"),
+			key.WithHelp("b/pgup", "page up"),
+		),
+		HalfPageUp: key.NewBinding(
+			key.WithKeys("u", "ctrl+u"),
+			key.WithHelp("u", "½ page up"),
+		),
+		HalfPageDown: key.NewBinding(
+			key.WithKeys("d", "ctrl+d"),
+			key.WithHelp("d", "½ page down"),
+		),
+		Up: key.NewBinding(
+			key.WithKeys("up", "k"),
+			key.WithHelp("↑/k", "up"),
+		),
+		Down: key.NewBinding(
+			key.WithKeys("down", "j"),
+			key.WithHelp("↓/j", "down"),
+		),
+	}
+}

viewport/viewport.go

@@ -4,26 +4,44 @@ import (
 	"math"
 	"strings"
 
+	"github.com/charmbracelet/bubbles/key"
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
 )
 
-const (
-	spacebar        = " "
-	mouseWheelDelta = 3
-)
+// New returns a new model with the given width and height as well as default
+// key mappings.
+func New(width, height int) (m Model) {
+	m.Width = width
+	m.Height = height
+	m.setInitialValues()
+	return m
+}
 
 // Model is the Bubble Tea model for this viewport element.
 type Model struct {
 	Width  int
 	Height int
+	KeyMap KeyMap
+
+	// Whether or not to respond to the mouse. The mouse must be enabled in
+	// Bubble Tea for this to work. For details, see the Bubble Tea docs.
+	MouseWheelEnabled bool
+
+	// The number of lines the mouse wheel will scroll. By default, this is 3.
+	MouseWheelDelta int
 
 	// YOffset is the vertical scroll position.
 	YOffset int
 
 	// YPosition is the position of the viewport in relation to the terminal
-	// window. It's used in high performance rendering.
+	// window. It's used in high performance rendering only.
 	YPosition int
 
+	// Style applies a lipgloss style to the viewport. Realistically, it's most
+	// useful for setting borders, margins and padding.
+	Style lipgloss.Style
+
 	// HighPerformanceRendering bypasses the normal Bubble Tea renderer to
 	// provide higher performance rendering. Most of the time the normal Bubble
 	// Tea rendering methods will suffice, but if you're passing content with
@@ -34,7 +52,20 @@ type Model struct {
 	// which is usually via the alternate screen buffer.
 	HighPerformanceRendering bool
 
-	lines []string
+	initialized bool
+	lines       []string
+}
+
+func (m *Model) setInitialValues() {
+	m.KeyMap = DefaultKeyMap()
+	m.MouseWheelEnabled = true
+	m.MouseWheelDelta = 3
+	m.initialized = true
+}
+
+// Init exists to satisfy the tea.Model interface for composability purposes.
+func (m Model) Init() tea.Cmd {
+	return nil
 }
 
 // AtTop returns whether or not the viewport is in the very top position.
@@ -45,13 +76,13 @@ func (m Model) AtTop() bool {
 // AtBottom returns whether or not the viewport is at or past the very bottom
 // position.
 func (m Model) AtBottom() bool {
-	return m.YOffset >= len(m.lines)-1-m.Height
+	return m.YOffset >= m.maxYOffset()
 }
 
 // PastBottom returns whether or not the viewport is scrolled beyond the last
 // line. This can happen when adjusting the viewport height.
 func (m Model) PastBottom() bool {
-	return m.YOffset > len(m.lines)-1-m.Height
+	return m.YOffset > m.maxYOffset()
 }
 
 // ScrollPercent returns the amount scrolled as a float between 0 and 1.
@@ -69,11 +100,22 @@ func (m Model) ScrollPercent() float64 {
 // SetContent set the pager's text content. For high performance rendering the
 // Sync command should also be called.
 func (m *Model) SetContent(s string) {
-	s = strings.Replace(s, "\r\n", "\n", -1) // normalize line endings
+	s = strings.ReplaceAll(s, "\r\n", "\n") // normalize line endings
 	m.lines = strings.Split(s, "\n")
+
+	if m.YOffset > len(m.lines)-1 {
+		m.GotoBottom()
+	}
 }
 
-// Return the lines that should currently be visible in the viewport.
+// maxYOffset returns the maximum possible value of the y-offset based on the
+// viewport's content and set height.
+func (m Model) maxYOffset() int {
+	return max(0, len(m.lines)-m.Height)
+}
+
+// visibleLines returns the lines that should currently be visible in the
+// viewport.
 func (m Model) visibleLines() (lines []string) {
 	if len(m.lines) > 0 {
 		top := max(0, m.YOffset)
@@ -83,6 +125,21 @@ func (m Model) visibleLines() (lines []string) {
 	return lines
 }
 
+// scrollArea returns the scrollable boundaries for high performance rendering.
+func (m Model) scrollArea() (top, bottom int) {
+	top = max(0, m.YPosition)
+	bottom = max(top, top+m.Height)
+	if top > 0 && bottom > top {
+		bottom--
+	}
+	return top, bottom
+}
+
+// SetYOffset sets the Y offset.
+func (m *Model) SetYOffset(n int) {
+	m.YOffset = clamp(n, 0, m.maxYOffset())
+}
+
 // ViewDown moves the view down by the number of lines in the viewport.
 // Basically, "page down".
 func (m *Model) ViewDown() []string {
@@ -90,11 +147,7 @@ func (m *Model) ViewDown() []string {
 		return nil
 	}
 
-	m.YOffset = min(
-		m.YOffset+m.Height,      // target
-		len(m.lines)-1-m.Height, // fallback
-	)
-
+	m.SetYOffset(m.YOffset + m.Height)
 	return m.visibleLines()
 }
 
@@ -104,11 +157,7 @@ func (m *Model) ViewUp() []string {
 		return nil
 	}
 
-	m.YOffset = max(
-		m.YOffset-m.Height, // target
-		0,                  // fallback
-	)
-
+	m.SetYOffset(m.YOffset - m.Height)
 	return m.visibleLines()
 }
 
@@ -118,18 +167,8 @@ func (m *Model) HalfViewDown() (lines []string) {
 		return nil
 	}
 
-	m.YOffset = min(
-		m.YOffset+m.Height/2,    // target
-		len(m.lines)-1-m.Height, // fallback
-	)
-
-	if len(m.lines) > 0 {
-		top := max(m.YOffset+m.Height/2, 0)
-		bottom := clamp(m.YOffset+m.Height, top, len(m.lines)-1)
-		lines = m.lines[top:bottom]
-	}
-
-	return lines
+	m.SetYOffset(m.YOffset + m.Height/2)
+	return m.visibleLines()
 }
 
 // HalfViewUp moves the view up by half the height of the viewport.
@@ -138,18 +177,8 @@ func (m *Model) HalfViewUp() (lines []string) {
 		return nil
 	}
 
-	m.YOffset = max(
-		m.YOffset-m.Height/2, // target
-		0,                    // fallback
-	)
-
-	if len(m.lines) > 0 {
-		top := max(m.YOffset, 0)
-		bottom := clamp(m.YOffset+m.Height/2, top, len(m.lines)-1)
-		lines = m.lines[top:bottom]
-	}
-
-	return lines
+	m.SetYOffset(m.YOffset - m.Height/2)
+	return m.visibleLines()
 }
 
 // LineDown moves the view down by the given number of lines.
@@ -161,21 +190,8 @@ func (m *Model) LineDown(n int) (lines []string) {
 	// Make sure the number of lines by which we're going to scroll isn't
 	// greater than the number of lines we actually have left before we reach
 	// the bottom.
-	maxDelta := (len(m.lines) - 1) - (m.YOffset + m.Height) // number of lines - viewport bottom edge
-	n = min(n, maxDelta)
-
-	m.YOffset = min(
-		m.YOffset+n,             // target
-		len(m.lines)-1-m.Height, // fallback
-	)
-
-	if len(m.lines) > 0 {
-		top := max(m.YOffset+m.Height-n, 0)
-		bottom := clamp(m.YOffset+m.Height, top, len(m.lines)-1)
-		lines = m.lines[top:bottom]
-	}
-
-	return lines
+	m.SetYOffset(m.YOffset + n)
+	return m.visibleLines()
 }
 
 // LineUp moves the view down by the given number of lines. Returns the new
@@ -187,17 +203,18 @@ func (m *Model) LineUp(n int) (lines []string) {
 
 	// Make sure the number of lines by which we're going to scroll isn't
 	// greater than the number of lines we are from the top.
-	n = min(n, m.YOffset)
+	m.SetYOffset(m.YOffset - n)
+	return m.visibleLines()
+}
 
-	m.YOffset = max(m.YOffset-n, 0)
+// TotalLineCount returns the total number of lines (both hidden and visible) within the viewport.
+func (m Model) TotalLineCount() int {
+	return len(m.lines)
+}
 
-	if len(m.lines) > 0 {
-		top := max(0, m.YOffset)
-		bottom := clamp(m.YOffset+n, top, len(m.lines)-1)
-		lines = m.lines[top:bottom]
-	}
-
-	return lines
+// VisibleLineCount returns the number of the visible lines within the viewport.
+func (m Model) VisibleLineCount() int {
+	return len(m.visibleLines())
 }
 
 // GotoTop sets the viewport to the top position.
@@ -206,32 +223,16 @@ func (m *Model) GotoTop() (lines []string) {
 		return nil
 	}
 
-	m.YOffset = 0
-
-	if len(m.lines) > 0 {
-		top := m.YOffset
-		bottom := clamp(m.YOffset+m.Height, top, len(m.lines)-1)
-		lines = m.lines[top:bottom]
-	}
-
-	return lines
+	m.SetYOffset(0)
+	return m.visibleLines()
 }
 
 // GotoBottom sets the viewport to the bottom position.
 func (m *Model) GotoBottom() (lines []string) {
-	m.YOffset = max(len(m.lines)-1-m.Height, 0)
-
-	if len(m.lines) > 0 {
-		top := m.YOffset
-		bottom := max(len(m.lines)-1, 0)
-		lines = m.lines[top:bottom]
-	}
-
-	return lines
+	m.SetYOffset(m.maxYOffset())
+	return m.visibleLines()
 }
 
-// COMMANDS
-
 // Sync tells the renderer where the viewport will be located and requests
 // a render of the current state of the viewport. It should be called for the
 // first render and after a window resize.
@@ -241,31 +242,22 @@ func Sync(m Model) tea.Cmd {
 	if len(m.lines) == 0 {
 		return nil
 	}
-
-	// TODO: we should probably use m.visibleLines() rather than these two
-	// expressions.
-	top := max(m.YOffset, 0)
-	bottom := clamp(m.YOffset+m.Height, 0, len(m.lines)-1)
-
-	return tea.SyncScrollArea(
-		m.lines[top:bottom],
-		m.YPosition,
-		m.YPosition+m.Height,
-	)
+	top, bottom := m.scrollArea()
+	return tea.SyncScrollArea(m.visibleLines(), top, bottom)
 }
 
 // ViewDown is a high performance command that moves the viewport up by a given
-// numer of lines. Use Model.ViewDown to get the lines that should be rendered.
+// number of lines. Use Model.ViewDown to get the lines that should be rendered.
 // For example:
 //
-//     lines := model.ViewDown(1)
-//     cmd := ViewDown(m, lines)
-//
+//	lines := model.ViewDown(1)
+//	cmd := ViewDown(m, lines)
 func ViewDown(m Model, lines []string) tea.Cmd {
 	if len(lines) == 0 {
 		return nil
 	}
-	return tea.ScrollDown(lines, m.YPosition, m.YPosition+m.Height)
+	top, bottom := m.scrollArea()
+	return tea.ScrollDown(lines, top, bottom)
 }
 
 // ViewUp is a high performance command the moves the viewport down by a given
@@ -275,57 +267,60 @@ func ViewUp(m Model, lines []string) tea.Cmd {
 	if len(lines) == 0 {
 		return nil
 	}
-	return tea.ScrollUp(lines, m.YPosition, m.YPosition+m.Height)
+	top, bottom := m.scrollArea()
+	return tea.ScrollUp(lines, top, bottom)
 }
 
-// UPDATE
-
-// Update runs the update loop with default keybindings similar to popular
-// pagers. To define your own keybindings use the methods on Model (i.e.
-// Model.LineDown()) and define your own update function.
+// Update handles standard message-based viewport updates.
 func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
+	var cmd tea.Cmd
+	m, cmd = m.updateAsModel(msg)
+	return m, cmd
+}
+
+// Author's note: this method has been broken out to make it easier to
+// potentially transition Update to satisfy tea.Model.
+func (m Model) updateAsModel(msg tea.Msg) (Model, tea.Cmd) {
+	if !m.initialized {
+		m.setInitialValues()
+	}
+
 	var cmd tea.Cmd
 
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
-		switch msg.String() {
-		// Down one page
-		case "pgdown", spacebar, "f":
+		switch {
+		case key.Matches(msg, m.KeyMap.PageDown):
 			lines := m.ViewDown()
 			if m.HighPerformanceRendering {
 				cmd = ViewDown(m, lines)
 			}
 
-		// Up one page
-		case "pgup", "b":
+		case key.Matches(msg, m.KeyMap.PageUp):
 			lines := m.ViewUp()
 			if m.HighPerformanceRendering {
 				cmd = ViewUp(m, lines)
 			}
 
-		// Down half page
-		case "d", "ctrl+d":
+		case key.Matches(msg, m.KeyMap.HalfPageDown):
 			lines := m.HalfViewDown()
 			if m.HighPerformanceRendering {
 				cmd = ViewDown(m, lines)
 			}
 
-		// Up half page
-		case "u", "ctrl+u":
+		case key.Matches(msg, m.KeyMap.HalfPageUp):
 			lines := m.HalfViewUp()
 			if m.HighPerformanceRendering {
 				cmd = ViewUp(m, lines)
 			}
 
-		// Down one line
-		case "down", "j":
+		case key.Matches(msg, m.KeyMap.Down):
 			lines := m.LineDown(1)
 			if m.HighPerformanceRendering {
 				cmd = ViewDown(m, lines)
 			}
 
-		// Up one line
-		case "up", "k":
+		case key.Matches(msg, m.KeyMap.Up):
 			lines := m.LineUp(1)
 			if m.HighPerformanceRendering {
 				cmd = ViewUp(m, lines)
@@ -333,15 +328,18 @@ func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 		}
 
 	case tea.MouseMsg:
+		if !m.MouseWheelEnabled {
+			break
+		}
 		switch msg.Type {
 		case tea.MouseWheelUp:
-			lines := m.LineUp(mouseWheelDelta)
+			lines := m.LineUp(m.MouseWheelDelta)
 			if m.HighPerformanceRendering {
 				cmd = ViewUp(m, lines)
 			}
 
 		case tea.MouseWheelDown:
-			lines := m.LineDown(mouseWheelDelta)
+			lines := m.LineDown(m.MouseWheelDelta)
 			if m.HighPerformanceRendering {
 				cmd = ViewDown(m, lines)
 			}
@@ -351,32 +349,39 @@ func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 	return m, cmd
 }
 
-// VIEW
-
 // View renders the viewport into a string.
 func (m Model) View() string {
 	if m.HighPerformanceRendering {
-		// Just send newlines since we're doing to be rendering the actual
-		// content seprately. We still need send something that equals the
+		// Just send newlines since we're going to be rendering the actual
+		// content separately. We still need to send something that equals the
 		// height of this view so that the Bubble Tea standard renderer can
 		// position anything below this view properly.
-		return strings.Repeat("\n", m.Height-1)
+		return strings.Repeat("\n", max(0, m.Height-1))
 	}
 
-	lines := m.visibleLines()
-
-	// Fill empty space with newlines
-	extraLines := ""
-	if len(lines) < m.Height {
-		extraLines = strings.Repeat("\n", m.Height-len(lines))
+	w, h := m.Width, m.Height
+	if sw := m.Style.GetWidth(); sw != 0 {
+		w = min(w, sw)
 	}
-
-	return strings.Join(lines, "\n") + extraLines
+	if sh := m.Style.GetHeight(); sh != 0 {
+		h = min(h, sh)
+	}
+	contentWidth := w - m.Style.GetHorizontalFrameSize()
+	contentHeight := h - m.Style.GetVerticalFrameSize()
+	contents := lipgloss.NewStyle().
+		Height(contentHeight).    // pad to height.
+		MaxHeight(contentHeight). // truncate height if taller.
+		MaxWidth(contentWidth).   // truncate width.
+		Render(strings.Join(m.visibleLines(), "\n"))
+	return m.Style.Copy().
+		UnsetWidth().UnsetHeight(). // Style size already applied in contents.
+		Render(contents)
 }
 
-// ETC
-
 func clamp(v, low, high int) int {
+	if high < low {
+		low, high = high, low
+	}
 	return min(high, max(low, v))
 }