@jsvision/ui / StatusItemView
Class: StatusItemView
Defined in: ui/src/status/status-item.ts:49
The presentational status entry view. Build one with statusItem and drop it into statusLine; the status line owns interaction, so you never wire events on it yourself.
Example
import { statusLine, statusItem, Commands, signal } from '@jsvision/ui';
const clock = signal('12:00:00');
const line = statusLine([
statusItem('~Alt-X~ Exit', Commands.quit, 'Alt+X'), // interactive command item
statusItem(() => clock()), // passive live label (no command)
]);Extends
Implements
Constructors
Constructor
new StatusItemView(
text,command?,key?):StatusItemView
Defined in: ui/src/status/status-item.ts:67
Parameters
text
string | (() => string)
The display label, or a () => string getter for a live one.
command?
string
Optional command to emit; omit for a passive label.
key?
string
Optional accelerator label, e.g. 'Alt+X'.
Returns
StatusItemView
Overrides
Properties
bounds
bounds:
Rect
Defined in: ui/src/view/view.ts:65
Parent-relative integer rect; written by the layout pass — read it in draw/hit-testing.
Inherited from
castsShadow
castsShadow:
boolean=false
Defined in: ui/src/view/view.ts:78
When true, the renderer paints a drop shadow on the cells just below and to the right of this view, in paint order (a later sibling's shadow falls over an earlier one). Default false. The Desktop sets it per window.
Inherited from
centered
centered:
boolean=false
Defined in: ui/src/view/view.ts:86
When true, the layout pass recentres this view within its parent after layout — origin = (parent - self) / 2 on both axes. Intended for absolutely-placed views (a modal dialog, a message box) whose size is fixed and whose origin would otherwise be placed by the caller. Default false; Dialog sets it when centered.
Inherited from
command?
readonlyoptionalcommand?:string
Defined in: ui/src/status/status-item.ts:53
The command emitted when activated; undefined for a passive label.
Implementation of
focusable
focusable:
boolean=false
Defined in: ui/src/view/view.ts:94
Whether this view can receive keyboard focus. Effective focusability also requires the view to be visible and enabled with no hidden/disabled ancestor. Default false; the focus manager drives the state.focused flag.
Inherited from
key?
readonlyoptionalkey?:string
Defined in: ui/src/status/status-item.ts:55
Optional accelerator label, e.g. 'Alt+X' or 'F4'.
Implementation of
layout
layout:
LayoutProps={}
Defined in: ui/src/view/view.ts:69
Layout props for this view (direction, size, padding, absolute placement, …).
Inherited from
postProcess
postProcess:
boolean=false
Defined in: ui/src/view/view.ts:98
Take part in the post-process sweep (after the focused view sees the event).
Inherited from
preProcess
preProcess:
boolean=false
Defined in: ui/src/view/view.ts:96
Take part in the pre-process sweep (root→down, before the focused view sees the event).
Inherited from
state
readonlystate:ViewState
Defined in: ui/src/view/view.ts:67
Draw-against flags. The object reference is fixed; individual fields mutate (e.g. focused).
Inherited from
text
readonlytext:string| (() =>string)
Defined in: ui/src/status/status-item.ts:51
Display label, or a getter for a live one; ~X~ marks the accent character.
Implementation of
Methods
accelerators()
accelerators(): readonly
string[]
Defined in: ui/src/view/view.ts:114
The Alt+hotkey accelerator characters (lowercase) this view claims in its focus scope, for duplicate-accelerator detection. The base returns none; accelerator-bearing widgets (Button/Label/CheckGroup/RadioGroup) override it to report their ~X~ hotkey(s).
Returns
readonly string[]
The claimed accelerator chars, or an empty list when the view claims none.
Inherited from
bind()
bind<
T>(reader,apply?,opts?):void
Defined in: ui/src/view/view.ts:228
Bind a reactive value to a redraw. Creates an effect (owned by this view's scope) that reads reader() — subscribing to whatever signals it touches — runs the optional apply(value), then requests a frame: a repaint by default, or a reflow when { relayout: true }. It re-runs automatically whenever those signals change, and is disposed when the view unmounts.
Call it from onMount, not the constructor — the view's scope only exists once mounted, so a pre-mount bind throws rather than silently dropping the binding.
Type Parameters
T
T
Parameters
reader
() => T
Reads the reactive source; the signals it reads become dependencies.
apply?
(v) => void
Optional: apply the read value to the widget (e.g. store it in a field).
opts?
Pass { relayout: true } when the change affects layout, so it reflows instead of just repainting.
relayout?
boolean
Returns
void
Example
import { signal } from '@jsvision/ui';
const count = signal(0);
// `status` is a View whose draw() reads count():
status.onMount(() => {
status.bind(() => count()); // repaint the status line whenever `count` changes
});Inherited from
derived()
protectedderived<T>(fn): () =>T
Defined in: ui/src/view/view.ts:261
Create a stable derived accessor owned by this view's scope. The returned () => T keeps the same identity for the life of the view, so it is safe to build in the constructor and hand to child views before this view mounts. The backing computed is created lazily under the view's own scope, so it is always owned and disposed at unmount — unlike a bare computed() in the constructor, which would run before any scope exists, leak, and warn.
Reads behave sensibly across the lifecycle:
- Before mount: evaluates
fn()directly (correct current value, nothing persisted). Good for a pre-mount natural-size measure. - After mount: builds and memoizes a
computed(fn)under the view's scope. - After an unmount→remount: the memo is keyed to the scope it was built under, so a remounted view (which gets a fresh scope) re-derives under the new scope instead of returning the previous mount's disposed, now-frozen computed — keeping a
Show/For-remounted widget reactive.
Type Parameters
T
T
Parameters
fn
() => T
The derivation (pure; the signals it reads become the computed's dependencies).
Returns
A stable accessor; call it to read the derived value.
() => T
Inherited from
desiredCaret()
desiredCaret():
Point|null
Defined in: ui/src/view/view.ts:192
Where this view wants the hardware text cursor, in view-local cells, or null for no cursor (the default — most views never show one). A focused text input overrides this to place the caret at the edit position; the event loop reads it after each frame, converts it to an absolute cell, and moves the terminal cursor there.
Returns
Point | null
The view-local caret point (0-based, relative to this view's origin), or null.
Inherited from
draw()
draw(
ctx):void
Defined in: ui/src/status/status-item.ts:104
Paint the label span and its ~…~ accent run(s). The span colour follows the pressed + enabled state pushed by the status line: pressed → the selected (green) palette, disabled → greyed; the accent run takes the matching hotkey colour (and lights up while the accelerator overlay is revealed) unless the item is disabled.
Parameters
ctx
The clipped, view-local paint context.
Returns
void
Overrides
focusSignal()
focusSignal():
Signal<void>
Defined in: ui/src/view/view.ts:136
Subscribe to this view's focus changes. Reading the returned signal inside a bind/effect re-runs that effect whenever this view gains or loses focus — including from another view (e.g. a Label repainting when the control it labels is focused). The signal notifies on every poke even without a value change. Lazy: the backing signal is created on first call.
Returns
Signal<void>
A signal that ticks whenever this view gains or loses focus.
Example
// Inside a widget's onMount, repaint whenever `other` view's focus changes:
this.onMount(() => this.bind(() => other.focusSignal()()));Inherited from
invalidate()
invalidate():
void
Defined in: ui/src/view/view.ts:197
Request a repaint of this view. A no-op before the view is mounted (the first frame paints everything).
Returns
void
Inherited from
invalidateLayout()
invalidateLayout():
void
Defined in: ui/src/view/view.ts:202
Request a reflow (re-run layout, then repaint). Use this when a change affects size/position, not just pixels.
Returns
void
Inherited from
measure()
measure():
Size2D
Defined in: ui/src/status/status-item.ts:92
Natural size: the display text plus one pad column on each side, one row tall — so items abut with no gap and a container's auto sizing gives each its exact span.
Returns
The { width, height: 1 } this item wants.
Overrides
onCleanup()
onCleanup(
fn):void
Defined in: ui/src/view/view.ts:298
Register a teardown callback that runs once when this view unmounts. Requires a mounted view — so call it from within onMount. Use it to release anything the view acquired (a timer, an external subscription).
Parameters
fn
() => void
The teardown callback.
Returns
void
Inherited from
onEvent()
onEvent(
_ev):void
Defined in: ui/src/view/view.ts:172
Handle an input event — a no-op by default. The event loop wraps each event in a DispatchEvent envelope and routes it to the views; override this to react to keys/mouse and set ev.handled = true to consume the event so it does not propagate further.
Parameters
_ev
The dispatch envelope (the wrapped event plus the mutable handled flag).
Returns
void
Inherited from
onMount()
onMount(
fn):void
Defined in: ui/src/view/view.ts:283
Register a callback to run once when the view becomes live (after its first layout gives it bounds). This is where to call bind, since the view's reactive scope exists by then. Registering after the view is already live runs the callback immediately.
Parameters
fn
() => void
Post-mount setup.
Returns
void
Inherited from
selectByClick()?
optionalselectByClick():void
Defined in: ui/src/view/view.ts:182
Optional "select + raise on click" hook. Left undefined on the base, so a plain view is not a select/raise target. A container that owns z-order (a Window) overrides it to select and raise itself. The hit-test invokes the first ancestor that defines this — before delivering the mouse-down — so a click always raises the window even if the interior also consumes the click.
Returns
void