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@jsvision/ui / Calendar

Class: Calendar ​

Documented in: Calendar

Defined in: ui/src/date/calendar.ts:110

A focusable month-grid day picker. Navigates a day cursor by keyboard and commits a day on Enter/Space or a single click.

Example ​

ts
import { Group, Calendar, signal, dayOfWeek, toISO } from '@jsvision/ui';
import type { CalendarDate } from '@jsvision/ui';

const g = new Group();
const value = signal<CalendarDate | null>(null);

const cal = new Calendar({
  value,
  firstDayOfWeek: 1,                 // Monday-first
  showWeekNumbers: true,
  isDisabled: (d) => dayOfWeek(d) === 0, // Sundays not selectable
  onChange: (d) => console.log('picked', toISO(d)),
});
const size = cal.measure();          // size the widget to the chosen density
cal.layout = { position: 'absolute', rect: { x: 1, y: 0, width: size.width, height: size.height } };
g.add(cal);

Extends ​

Constructors ​

Constructor ​

new Calendar(opts): Calendar

Defined in: ui/src/date/calendar.ts:137

Parameters ​

opts ​

CalendarOptions

The two-way value plus optional today/min/max/isDisabled/firstDayOfWeek/ showWeekNumbers/density/onChange.

Returns ​

Calendar

Overrides ​

View.constructor

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 ​

View.bounds

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 ​

View.castsShadow

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 ​

View.centered

cursor ​

protected readonly cursor: Signal<CalendarDate>

Defined in: ui/src/date/calendar.ts:131

The focus cursor cell (starts at value ?? today, clamped into [min,max]).

firstDayOfWeek ​

protected readonly firstDayOfWeek: 0 | 1

Defined in: ui/src/date/calendar.ts:121

focusable ​

focusable: boolean = true

Defined in: ui/src/date/calendar.ts:112

The calendar takes focus so its day cursor and keymap are scoped to it.

Overrides ​

View.focusable

isDisabled? ​

protected readonly optional isDisabled?: (date) => boolean

Defined in: ui/src/date/calendar.ts:120

Parameters ​

date ​

CalendarDate

Returns ​

boolean

layout ​

layout: LayoutProps = {}

Defined in: ui/src/view/view.ts:69

Layout props for this view (direction, size, padding, absolute placement, …).

Inherited from ​

View.layout

max? ​

protected readonly optional max?: CalendarDate

Defined in: ui/src/date/calendar.ts:119

metrics ​

protected readonly metrics: CalendarMetrics

Defined in: ui/src/date/calendar.ts:125

Resolved layout geometry for the chosen density + week-number flag (computed once).

min? ​

protected readonly optional min?: CalendarDate

Defined in: ui/src/date/calendar.ts:118

onChange? ​

protected readonly optional onChange?: (date) => void

Defined in: ui/src/date/calendar.ts:123

Parameters ​

date ​

CalendarDate

Returns ​

void

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 ​

View.postProcess

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 ​

View.preProcess

showWeekNumbers ​

protected readonly showWeekNumbers: boolean

Defined in: ui/src/date/calendar.ts:122

state ​

readonly state: 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 ​

View.state

todayDate ​

protected readonly todayDate: CalendarDate

Defined in: ui/src/date/calendar.ts:117

value ​

readonly value: Signal<CalendarDate | null>

Defined in: ui/src/date/calendar.ts:115

Two-way selected day (null = none).

visibleMonth ​

protected readonly visibleMonth: Signal<number>

Defined in: ui/src/date/calendar.ts:129

visibleYear ​

protected readonly visibleYear: Signal<number>

Defined in: ui/src/date/calendar.ts:128

The shown month (reactive — month nav repaints).

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 ​

View.accelerators

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 ​

ts
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 ​

View.bind

cellRole() ​

protected cellRole(date): keyof Theme

Defined in: ui/src/date/calendar.ts:275

Resolve a day cell's theme colour by precedence: cursor (only while focused) > selected > today > disabled > normal.

Parameters ​

date ​

CalendarDate

Returns ​

keyof Theme

clampBounds() ​

protected clampBounds(d): CalendarDate

Defined in: ui/src/date/calendar.ts:173

Clamp a date into [min,max] (only where the respective bound is set); the cursor never leaves it.

Parameters ​

d ​

CalendarDate

Returns ​

CalendarDate

clampVisibleMonth() ​

protected clampVisibleMonth(year, month): object

Defined in: ui/src/date/calendar.ts:209

Clamp a visible (year, month) into [min,max] at month granularity (a bound's day is ignored): the visible view can never page earlier than min's month nor later than max's month (only where the respective bound is set). Returns the clamped month via a linear month index.

Parameters ​

year ​

number

month ​

number

Returns ​

object

month ​

month: number

year ​

year: number

commit() ​

protected commit(d): void

Defined in: ui/src/date/calendar.ts:188

Commit a date to value (+ onChange); a disabled or out-of-range date is a no-op.

Parameters ​

d ​

CalendarDate

Returns ​

void

currentGrid() ​

protected currentGrid(): MonthGrid

Defined in: ui/src/date/calendar.ts:264

Build the current month's grid (pure; shared by draw + mouse hit-test).

Returns ​

MonthGrid

derived() ​

protected derived<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 ​

View.derived

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 ​

View.desiredCaret

draw() ​

draw(ctx): void

Defined in: ui/src/date/calendar.ts:286

Paint the header, weekday row, 6 grid rows, and (comfortable/spacious) the footer, per the metrics.

Parameters ​

ctx ​

DrawContext

Returns ​

void

Overrides ​

View.draw

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 ​

ts
// Inside a widget's onMount, repaint whenever `other` view's focus changes:
this.onMount(() => this.bind(() => other.focusSignal()()));

Inherited from ​

View.focusSignal

goToMonth() ​

goToMonth(year, month): void

Defined in: ui/src/date/calendar.ts:258

Change the visible month only (value + cursor unchanged).

Parameters ​

year ​

number

month ​

number

Returns ​

void

handleMouse() ​

protected handleMouse(ev): void

Defined in: ui/src/date/calendar.ts:381

Header ↑↓ hit columns + the footer Today button + day-click commit — all keyed off the metrics.

Parameters ​

ev ​

DispatchEvent

Returns ​

void

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 ​

View.invalidate

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 ​

View.invalidateLayout

isCommittable() ​

protected isCommittable(d): boolean

Defined in: ui/src/date/calendar.ts:180

True when a date may be committed — not disabled and within [min,max].

Parameters ​

d ​

CalendarDate

Returns ​

boolean

measure() ​

measure(): Size2D

Defined in: ui/src/date/calendar.ts:168

Advertise the density's intrinsic size (width × height) for auto sizing.

Returns ​

Size2D

Overrides ​

View.measure

moveCursor() ​

protected moveCursor(target): void

Defined in: ui/src/date/calendar.ts:195

Move the cursor (clamped), re-pointing the visible month when the target's month differs.

Parameters ​

target ​

CalendarDate

Returns ​

void

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 ​

View.onCleanup

onEvent() ​

onEvent(ev): void

Defined in: ui/src/date/calendar.ts:327

Handle keyboard (cursor/month/year navigation + commit) and mouse (header arrows, footer Today, day-click commit). Plain arrow keys are always consumed so navigation never leaves the calendar.

Parameters ​

ev ​

DispatchEvent

The dispatch envelope.

Returns ​

void

Overrides ​

View.onEvent

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 ​

View.onMount

select() ​

select(date): void

Defined in: ui/src/date/calendar.ts:245

Programmatically commit a day (respects disabled/bounds — a no-op if the day is not committable).

Parameters ​

date ​

CalendarDate

Returns ​

void

selectByClick()? ​

optional selectByClick(): 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

Inherited from ​

View.selectByClick

shiftMonth() ​

protected shiftMonth(delta): void

Defined in: ui/src/date/calendar.ts:220

Shift the visible month by delta, clamped to [min,max] (the cursor and value are untouched — the +/- keys and the left header ↑↓ arrows). At a bound edge the shift is a no-op.

Parameters ​

delta ​

number

Returns ​

void

shiftYear() ​

protected shiftYear(delta): void

Defined in: ui/src/date/calendar.ts:231

Shift the visible year by delta (month kept), clamped to [min,max] (the right header ↑↓ arrows). Clamping can pull the month to the bound's month when the target year lands on a boundary year.

Parameters ​

delta ​

number

Returns ​

void

today() ​

today(): void

Defined in: ui/src/date/calendar.ts:250

Move the cursor + visible month to today.

Returns ​

void

weekBoundary() ​

protected weekBoundary(cur, which): CalendarDate

Defined in: ui/src/date/calendar.ts:238

The first (or last) day of the cursor's displayed week (rotated by firstDayOfWeek).

Parameters ​

cur ​

CalendarDate

which ​

"first" | "last"

Returns ​

CalendarDate