fix(progress): update progress bar threshold method per changes in d897463

The design was overly complicated, especially for such subtle benefits.

.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 }}"

README.md

@@ -149,8 +149,8 @@ var DefaultKeyMap = KeyMap{
         key.WithHelp("↑/k", "move up"), // corresponding help text
     ),
     Down: key.NewBinding(
-        WithKeys("j", "down"),
-        WithHelp("↓/j", "move down"),
+        key.WithKeys("j", "down"),
+        key.WithHelp("↓/j", "move down"),
     ),
 }
 
@@ -171,13 +171,24 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 ## Additional Bubbles
 
-* [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.
+* [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.
 * [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).

go.mod

@@ -3,10 +3,10 @@ module github.com/charmbracelet/bubbles
 go 1.13
 
 require (
-	github.com/atotto/clipboard v0.1.2
+	github.com/atotto/clipboard v0.1.4
 	github.com/charmbracelet/bubbletea v0.19.3
 	github.com/charmbracelet/harmonica v0.1.0
-	github.com/charmbracelet/lipgloss v0.3.0
+	github.com/charmbracelet/lipgloss v0.4.0
 	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0
 	github.com/mattn/go-runewidth v0.0.13

go.sum

@@ -1,18 +1,17 @@
-github.com/atotto/clipboard v0.1.2 h1:YZCtFu5Ie8qX2VmVTBnrqLSiU9XOWwqNRmdT3gIQzbY=
-github.com/atotto/clipboard v0.1.2/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
+github.com/atotto/clipboard v0.1.4 h1:EH0zSVneZPSuFR11BlR9YppQTVDbh5+16AmcJi4g1z4=
+github.com/atotto/clipboard v0.1.4/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
 github.com/charmbracelet/bubbletea v0.19.3 h1:OKeO/Y13rQQqt4snX+lePB0QrnW80UdrMNolnCcmoAw=
 github.com/charmbracelet/bubbletea v0.19.3/go.mod h1:VuXF2pToRxDUHcBUcPmCRUHRvFATM4Ckb/ql1rBl3KA=
 github.com/charmbracelet/harmonica v0.1.0 h1:lFKeSd6OAckQ/CEzPVd2mqj+YMEubQ/3FM2IYY3xNm0=
 github.com/charmbracelet/harmonica v0.1.0/go.mod h1:KSri/1RMQOZLbw7AHqgcBycp8pgJnQMYYT8QZRqZ1Ao=
-github.com/charmbracelet/lipgloss v0.3.0 h1:5MysOD6sHr4RP4jkZNWGVIul5GKoOsP12NgbgXPvAlA=
-github.com/charmbracelet/lipgloss v0.3.0/go.mod h1:VkhdBS2eNAmRkTwRKLJCFhCOVkjntMusBDxv7TXahuk=
+github.com/charmbracelet/lipgloss v0.4.0 h1:768h64EFkGUr8V5yAKV7/Ta0NiVceiPaV+PphaW1K9g=
+github.com/charmbracelet/lipgloss v0.4.0/go.mod h1:vmdkHvce7UzX6xkyf4cca8WlwdQ5RQr8fzta+xl7BOM=
 github.com/containerd/console v1.0.2 h1:Pi6D+aZXM+oUw1czuKgH5IJ+y0jhYcwBJfx5/Ghn9dE=
 github.com/containerd/console v1.0.2/go.mod h1:ytZPjGgY2oeTkAONYafi2kSj0aYggsf8acV1PGKCbzQ=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
-github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
 github.com/mattn/go-isatty v0.0.13 h1:qdl+GuBjcsKKDco5BsxPJlId98mSWNKqYA+Co0SC1yA=
 github.com/mattn/go-isatty v0.0.13/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
 github.com/mattn/go-runewidth v0.0.10/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
@@ -24,7 +23,6 @@ github.com/muesli/ansi v0.0.0-20211018074035-2e021307bc4b/go.mod h1:fQuZ0gauxyBc
 github.com/muesli/reflow v0.2.1-0.20210115123740-9e1d0d53df68/go.mod h1:Xk+z4oIWdQqJzsxyjgl3P22oYZnHdZ8FFTHAQQt5BMQ=
 github.com/muesli/reflow v0.3.0 h1:IFsN6K9NfGtjeggFP+68I4chLZV2yIKsXJFNZ+eWh6s=
 github.com/muesli/reflow v0.3.0/go.mod h1:pbwTDkVPibjO2kyvBQRBxTWEEGDGq0FlB1BIKtnHY/8=
-github.com/muesli/termenv v0.8.1/go.mod h1:kzt/D/4a88RoheZmwfqorY3A+tnsSMA9HJC/fQSFKo0=
 github.com/muesli/termenv v0.9.0 h1:wnbOaGz+LUR3jNT0zOzinPnyDaCZUQRZj9GxK8eRVl8=
 github.com/muesli/termenv v0.9.0/go.mod h1:R/LzAKf+suGs4IsO95y7+7DpFHO0KABgnZqtlyx2mBw=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=

help/help.go

@@ -165,7 +165,12 @@ func (m Model) FullHelpView(groups [][]key.Binding) string {
 	}
 
 	var (
+		// Linter note: at this time we don't think it's worth the additional
+		// code complexity involved in preallocating this slice.
+		//
+		//nolint:prealloc
 		out []string
+
 		totalWidth int
 		sep        = m.Styles.FullSeparator.Render(m.FullSeparator)
 		sepWidth   = lipgloss.Width(sep)

key/key.go

@@ -13,8 +13,8 @@
 //             key.WithHelp("↑/k", "move up"), // corresponding help text
 //         ),
 //         Down: key.NewBinding(
-//             WithKeys("j", "down"),
-//             WithHelp("↓/j", "move down"),
+//             key.WithKeys("j", "down"),
+//             key.WithHelp("↓/j", "move down"),
 //         ),
 //     }
 //

list/list.go

@@ -67,15 +67,37 @@ func (f filteredItems) items() []Item {
 	return agg
 }
 
-func (f filteredItems) matches() [][]int {
-	agg := make([][]int, len(f))
-	for i, v := range f {
-		agg[i] = v.matches
-	}
-	return agg
+// FilterMatchesMsg contains data about items matched during filtering. The
+// message should be routed to Update for processing.
+type FilterMatchesMsg []filteredItem
+
+// FilterFunc takes a term and a list of strings to search through
+// (defined by Item#FilterValue).
+// It should return a sorted list of ranks.
+type FilterFunc func(string, []string) []Rank
+
+// Rank defines a rank for a given item.
+type Rank struct {
+	// The index of the item in the original input.
+	Index int
+	// Indices of the actual word that were matched against the filter term.
+	MatchedIndexes []int
 }
 
-type FilterMatchesMsg []filteredItem
+// DefaultFilter uses the sahilm/fuzzy to filter through the list.
+// This is set by default.
+func DefaultFilter(term string, targets []string) []Rank {
+	var ranks fuzzy.Matches = fuzzy.Find(term, targets)
+	sort.Stable(ranks)
+	result := make([]Rank, len(ranks))
+	for i, r := range ranks {
+		result[i] = Rank{
+			Index:          r.Index,
+			MatchedIndexes: r.MatchedIndexes,
+		}
+	}
+	return result
+}
 
 type statusMessageTimeoutMsg struct{}
 
@@ -113,6 +135,11 @@ type Model struct {
 	// Key mappings for navigating the list.
 	KeyMap KeyMap
 
+	// Filter is used to filter the list.
+	Filter FilterFunc
+
+	disableQuitKeybindings bool
+
 	// Additional key mappings for the short and full help views. This allows
 	// you to add additional key mappings to the help menu without
 	// re-implementing the help component. Of course, you can also disable the
@@ -177,6 +204,7 @@ func New(items []Item, delegate ItemDelegate, width, height int) Model {
 		showHelp:              true,
 		filteringEnabled:      true,
 		KeyMap:                DefaultKeyMap(),
+		Filter:                DefaultFilter,
 		Styles:                styles,
 		Title:                 "List",
 		FilterInput:           filterInput,
@@ -330,7 +358,8 @@ func (m *Model) SetItem(index int, item Item) tea.Cmd {
 	return cmd
 }
 
-// Insert an item at the given index. This returns a command.
+// Insert an item at the given index. If index is out of the upper bound, the
+// item will be appended. This returns a command.
 func (m *Model) InsertItem(index int, item Item) tea.Cmd {
 	var cmd tea.Cmd
 	m.items = insertItemIntoSlice(m.items, item, index)
@@ -526,6 +555,7 @@ func (m *Model) StopSpinner() {
 // Helper for disabling the keybindings used for quitting, incase you want to
 // handle this elsewhere in your application.
 func (m *Model) DisableQuitKeybindings() {
+	m.disableQuitKeybindings = true
 	m.KeyMap.Quit.SetEnabled(false)
 	m.KeyMap.ForceQuit.SetEnabled(false)
 }
@@ -608,7 +638,7 @@ func (m *Model) updateKeybindings() {
 		m.KeyMap.ClearFilter.SetEnabled(false)
 		m.KeyMap.CancelWhileFiltering.SetEnabled(true)
 		m.KeyMap.AcceptWhileFiltering.SetEnabled(m.FilterInput.Value() != "")
-		m.KeyMap.Quit.SetEnabled(true)
+		m.KeyMap.Quit.SetEnabled(false)
 		m.KeyMap.ShowFullHelp.SetEnabled(false)
 		m.KeyMap.CloseFullHelp.SetEnabled(false)
 
@@ -628,7 +658,7 @@ func (m *Model) updateKeybindings() {
 		m.KeyMap.ClearFilter.SetEnabled(m.filterState == FilterApplied)
 		m.KeyMap.CancelWhileFiltering.SetEnabled(false)
 		m.KeyMap.AcceptWhileFiltering.SetEnabled(false)
-		m.KeyMap.Quit.SetEnabled(true)
+		m.KeyMap.Quit.SetEnabled(!m.disableQuitKeybindings)
 
 		if m.Help.ShowAll {
 			m.KeyMap.ShowFullHelp.SetEnabled(true)
@@ -1084,7 +1114,7 @@ func (m Model) populatedView() string {
 		if m.filterState == Filtering {
 			return ""
 		}
-		m.Styles.NoItems.Render("No items found.")
+		return m.Styles.NoItems.Render("No items found.")
 	}
 
 	if len(items) > 0 {
@@ -1135,11 +1165,8 @@ func filterItems(m Model) tea.Cmd {
 			targets = append(targets, t.FilterValue())
 		}
 
-		var ranks fuzzy.Matches = fuzzy.Find(m.FilterInput.Value(), targets)
-		sort.Stable(ranks)
-
 		filterMatches := []filteredItem{}
-		for _, r := range ranks {
+		for _, r := range m.Filter(m.FilterInput.Value(), targets) {
 			filterMatches = append(filterMatches, filteredItem{
 				item:    items[r.Index],
 				matches: r.MatchedIndexes,

progress/progress.go

@@ -35,6 +35,7 @@ const (
 	defaultWidth         = 40
 	defaultFrequency     = 18.0
 	defaultDamping       = 1.0
+	defaultAnimThreshold = 0.08
 )
 
 var color func(string) termenv.Color = termenv.ColorProfile().Color
@@ -98,6 +99,11 @@ func WithWidth(w int) Option {
 	}
 }
 
+// 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)
@@ -105,6 +111,14 @@ func WithSpringOptions(frequency, damping float64) Option {
 	}
 }
 
+// WithAnimationThreshold sets the percent chagne threshold necessary to
+// trigger an animated transition.
+func WithAnimationThreshold(ratio float64) Option {
+	return func(m *Model) {
+		m.SetAnimationThreshold(ratio)
+	}
+}
+
 // FrameMsg indicates that an animation step should occur.
 type FrameMsg struct {
 	id  int
@@ -136,13 +150,17 @@ type Model struct {
 	PercentFormat   string // a fmt string for a float
 	PercentageStyle lipgloss.Style
 
-	// Members for animated transitions.
+	// Settings for animated transitions.
 	spring           harmonica.Spring
 	springCustomized bool
-	percent          float64
-	targetPercent    float64
+	percentShown     float64 // percent currently displaying
+	targetPercent    float64 // percent to which we're animating
 	velocity         float64
 
+	// The amount of change required to trigger an animated transition. Should
+	// be a float between 0 and 1.
+	animThreshold float64
+
 	// Gradient settings
 	useRamp    bool
 	rampColorA colorful.Color
@@ -198,12 +216,12 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		}
 
 		// If we've more or less reached equilibrium, stop updating.
-		dist := math.Abs(m.percent - m.targetPercent)
+		dist := math.Abs(m.percentShown - m.targetPercent)
 		if dist < 0.001 && m.velocity < 0.01 {
 			return m, nil
 		}
 
-		m.percent, m.velocity = m.spring.Update(m.percent, m.velocity, m.targetPercent)
+		m.percentShown, m.velocity = m.spring.Update(m.percentShown, m.velocity, m.targetPercent)
 		return m, m.nextFrame()
 
 	default:
@@ -213,12 +231,13 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 // 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.
+//
+// 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 percentage state of the model. This is only
+// 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.
@@ -231,7 +250,14 @@ func (m Model) Percent() float64 {
 //
 // 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))
+	// If the value is at or below the animation threshold, don't animate
+	if math.Abs(p-m.percentShown) <= m.animThreshold {
+		m.percentShown = asRatio(p)
+		m.targetPercent = asRatio(p)
+		return nil
+	}
+
+	m.targetPercent = asRatio(p)
 	m.tag++
 	return m.nextFrame()
 }
@@ -252,10 +278,22 @@ func (m *Model) DecrPercent(v float64) tea.Cmd {
 	return m.SetPercent(m.Percent() - v)
 }
 
+// SetAnimationThreshold sets the percent chagne threshold necessary to trigger
+// an animated transition.
+func (m *Model) SetAnimationThreshold(v float64) {
+	m.animThreshold = asRatio(v)
+}
+
+// AnimationThreshold returns the percent change necessary to trigger an
+// animated transition.
+func (m *Model) AnimationThreshold() float64 {
+	return m.animThreshold
+}
+
 // 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.percent)
+	return m.ViewAs(m.percentShown)
 }
 
 // ViewAs renders the progress bar with a given percentage.
@@ -345,3 +383,7 @@ func min(a, b int) int {
 	}
 	return b
 }
+
+func asRatio(v float64) float64 {
+	return math.Max(math.Min(v, 1), 0)
+}

spinner/spinner.go

@@ -1,13 +1,11 @@
 package spinner
 
 import (
-	"strings"
 	"sync"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
-	"github.com/muesli/reflow/ansi"
 )
 
 // Internal ID management for text inputs. Necessary for blink integrity when
@@ -85,114 +83,17 @@ 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
 	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()
-}
-
-// 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{}
-	}
-}
-
 // ID returns the spinner's unique ID.
 func (m Model) ID() int {
 	return m.id
 }
 
-// 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
-	}
-	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()
-}
-
 // New returns a model with default values.
 func New() Model {
 	return Model{
@@ -250,16 +151,7 @@ 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

textinput/textinput.go

@@ -62,7 +62,7 @@ const (
 	// seen for password fields on the command line.
 	EchoNone
 
-	// EchoOnEdit
+	// EchoOnEdit.
 )
 
 // blinkCtx manages cursor blinking.
@@ -203,6 +203,11 @@ func (m Model) Cursor() int {
 	return m.pos
 }
 
+// Blink returns whether or not to draw the cursor.
+func (m Model) Blink() bool {
+	return m.blink
+}
+
 // 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.
 func (m *Model) SetCursor(pos int) {
@@ -234,7 +239,7 @@ func (m *Model) cursorStart() bool {
 	return m.setCursor(0)
 }
 
-// CursorEnd moves the cursor to the end of the input field
+// CursorEnd moves the cursor to the end of the input field.
 func (m *Model) CursorEnd() {
 	m.cursorEnd()
 }
@@ -412,7 +417,11 @@ func (m *Model) deleteWordLeft() bool {
 		return m.deleteBeforeCursor()
 	}
 
-	i := m.pos
+	// 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
+
 	blink := m.setCursor(m.pos - 1)
 	for unicode.IsSpace(m.value[m.pos]) {
 		if m.pos <= 0 {
@@ -434,10 +443,10 @@ func (m *Model) deleteWordLeft() bool {
 		}
 	}
 
-	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
@@ -455,7 +464,7 @@ func (m *Model) deleteWordRight() bool {
 		return m.deleteAfterCursor()
 	}
 
-	i := m.pos
+	oldPos := m.pos
 	m.setCursor(m.pos + 1)
 	for unicode.IsSpace(m.value[m.pos]) {
 		// ignore series of whitespace after cursor
@@ -475,12 +484,12 @@ 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)
+	return m.setCursor(oldPos)
 }
 
 // wordLeft moves the cursor one word to the left. Returns whether or not the
@@ -796,6 +805,9 @@ func Paste() tea.Msg {
 }
 
 func clamp(v, low, high int) int {
+	if high < low {
+		low, high = high, low
+	}
 	return min(high, max(low, v))
 }
 

viewport/viewport.go

@@ -76,13 +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)-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)-m.Height
+	return m.YOffset > m.maxYOffset()
 }
 
 // ScrollPercent returns the amount scrolled as a float between 0 and 1.
@@ -108,6 +108,12 @@ func (m *Model) SetContent(s string) {
 	}
 }
 
+// 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) {
@@ -131,7 +137,7 @@ func (m Model) scrollArea() (top, bottom int) {
 
 // SetYOffset sets the Y offset.
 func (m *Model) SetYOffset(n int) {
-	m.YOffset = clamp(n, 0, len(m.lines)-m.Height)
+	m.YOffset = clamp(n, 0, m.maxYOffset())
 }
 
 // ViewDown moves the view down by the number of lines in the viewport.
@@ -213,12 +219,10 @@ func (m *Model) GotoTop() (lines []string) {
 
 // GotoBottom sets the viewport to the bottom position.
 func (m *Model) GotoBottom() (lines []string) {
-	m.SetYOffset(len(m.lines) - 1 - m.Height)
+	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.
@@ -354,12 +358,16 @@ func (m Model) View() string {
 		extraLines = strings.Repeat("\n", max(0, m.Height-len(lines)))
 	}
 
-	return m.Style.Render(strings.Join(lines, "\n") + extraLines)
+	return m.Style.Copy().
+		UnsetWidth().
+		UnsetHeight().
+		Render(strings.Join(lines, "\n") + extraLines)
 }
 
-// ETC
-
 func clamp(v, low, high int) int {
+	if high < low {
+		low, high = high, low
+	}
 	return min(high, max(low, v))
 }