@jsvision/ui / Memo
Class: Memo
Documented in: Memo
Defined in: ui/src/editor/memo.ts:35
A dialog-embeddable, signal-bound multiline editor.
Memo is an Editor styled for the gray dialog palette and safe to place among other controls: it lets Tab pass through, so dialog focus traversal still works. Its content is bound to a signal — typing writes the signal the same tick, and writing the signal from outside replaces the buffer — so you read and write the memo's text through that signal rather than through the editor.
Example
import { Dialog, Memo, signal, at } from '@jsvision/ui';
const notes = signal('initial text');
const memo = new Memo({ value: notes });
const dialog = new Dialog({ title: 'Notes', width: 46, height: 14 });
dialog.add(at(memo, 2, 2, 40, 8));
// Read the bound signal (e.g. inside an effect) to observe edits; write it to replace the buffer.
notes.set('replaced from outside'); // updates the memo's buffer
console.log('memo text is', notes());Extends
Constructors
Constructor
new Memo(
options):Memo
Defined in: ui/src/editor/memo.ts:41
Parameters
options
Returns
Memo
Overrides
Properties
autoIndentOn
autoIndentOn:
boolean
Defined in: ui/src/editor/editor.ts:106
Inherited from
bounds
bounds:
Rect
Defined in: ui/src/view/view.ts:66
Parent-relative integer rect; written by the layout pass — read it in draw/hit-testing.
Inherited from
canRedo
readonlycanRedo:Signal<boolean>
Defined in: ui/src/editor/editor.ts:92
Inherited from
canUndo
readonlycanUndo:Signal<boolean>
Defined in: ui/src/editor/editor.ts:91
Whether an undo / redo step is available.
Inherited from
castsShadow
castsShadow:
boolean=false
Defined in: ui/src/view/view.ts:97
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:105
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
curPos
readonlycurPos:Signal<{col:number;line:number; }>
Defined in: ui/src/editor/editor.ts:83
The caret as 1-based {line, col} (col is the visual column).
Inherited from
curPtr
curPtr:
number=0
Defined in: ui/src/editor/editor.ts:100
Inherited from
curY
curY:
number=0
Defined in: ui/src/editor/editor.ts:109
Inherited from
delta
readonlydelta:object
Defined in: ui/src/editor/editor.ts:94
The scroll offset, as a pair of signals — also the value channel for scroll bars: a bar bound to delta.x/delta.y scrolls the editor on any write (clamped to the content).
x
readonlyx:Signal<number>
y
readonlyy:Signal<number>
Inherited from
doReplace
doReplace:
boolean=false
Defined in: ui/src/editor/editor.ts:257
Inherited from
drawLine
drawLine:
number=0
Defined in: ui/src/editor/editor.ts:110
Inherited from
drawPtrP
drawPtrP:
number=0
Defined in: ui/src/editor/editor.ts:111
Inherited from
eolKind
eolKind:
LineEnding='lf'
Defined in: ui/src/editor/editor.ts:99
Inherited from
focusable
focusable:
boolean=true
Defined in: ui/src/editor/editor.ts:75
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
grabsFocus
grabsFocus:
boolean=true
Defined in: ui/src/view/view.ts:122
Whether a mouse-down that hits this view moves keyboard focus to it. Default true — the usual click-to-focus. Set false for a control that should act on a click without stealing focus from whatever is focused (e.g. a dialog Cancel button, or a toolbar/stepper button): the click still dispatches, but the previously-focused view keeps focus, so it never fires a focus-leave side effect such as a field's blur-validation. Independent of focusable — a grabsFocus: false view can still be reached by Tab and activated by Space.
Inherited from
hasSelection
readonlyhasSelection:Signal<boolean>
Defined in: ui/src/editor/editor.ts:85
Whether any text is currently selected.
Inherited from
indicator
indicator:
IndicatorTarget|null=null
Defined in: ui/src/editor/editor.ts:134
Inherited from
insertMode
readonlyinsertMode:Signal<boolean>
Defined in: ui/src/editor/editor.ts:87
true = insert mode, false = overwrite mode; the Insert key toggles it.
Inherited from
keyBindings
readonlykeyBindings:EditorKeyBindings
Defined in: ui/src/editor/editor.ts:115
Inherited from
layout
readonlylayout:Readonly<LayoutProps> ={}
Defined in: ui/src/view/view.ts:88
Layout props for this view (direction, size, padding, absolute placement, …) — read-only.
Change them with setLayout, which is the only writer. The field and every prop on it are closed, so neither view.layout = {…} nor view.layout.rect = {…} compiles, and neither does editing a solved rect a field at a time (view.layout.rect.x = 5). That is deliberate: a wholesale assignment silently drops every prop it omits and never reflows, and an in-place prop write reflows only if you remember to ask.
Read it freely — this is where a view's solved intent lives, and layout.rect is how an absolutely-placed view reports where it was put.
Inherited from
limitY
limitY:
number=1
Defined in: ui/src/editor/editor.ts:112
Inherited from
lineCount
readonlylineCount:Signal<number>
Defined in: ui/src/editor/editor.ts:89
The number of lines in the buffer.
Inherited from
modified
readonlymodified:Signal<boolean>
Defined in: ui/src/editor/editor.ts:81
Whether the buffer has unsaved changes since it was last loaded or saved.
Inherited from
normalRole
protectednormalRole: keyofTheme='editorNormal'
Defined in: ui/src/editor/editor.ts:137
The normal/selected theme roles; Memo overrides them to the gray-dialog palette.
Inherited from
options
readonlyoptions:EditorOptions
Defined in: ui/src/editor/editor.ts:120
Inherited from
overwrite
overwrite:
boolean
Defined in: ui/src/editor/editor.ts:105
Inherited from
postProcess
postProcess:
boolean=false
Defined in: ui/src/view/view.ts:126
Take part in the post-process sweep (after the focused view sees the event).
Inherited from
preProcess
preProcess:
boolean=true
Defined in: ui/src/editor/editor.ts:77
Sees keys before app chrome so the focused editor can claim the WordStar Ctrl-Q/Ctrl-K prefixes.
Inherited from
promptOnReplace
promptOnReplace:
boolean=true
Defined in: ui/src/editor/editor.ts:255
Inherited from
replaceAllFlag
replaceAllFlag:
boolean=false
Defined in: ui/src/editor/editor.ts:256
Inherited from
replaceStr
replaceStr:
string=''
Defined in: ui/src/editor/editor.ts:253
Inherited from
searchOpts
searchOpts:
SearchOptions
Defined in: ui/src/editor/editor.ts:254
Inherited from
selectedRole
protectedselectedRole: keyofTheme='editorSelected'
Defined in: ui/src/editor/editor.ts:138
Inherited from
selecting
selecting:
boolean=false
Defined in: ui/src/editor/editor.ts:104
Inherited from
selEndP
selEndP:
number=0
Defined in: ui/src/editor/editor.ts:103
Inherited from
state
readonlystate:ViewState
Defined in: ui/src/view/view.ts:75
Draw-against flags. The object reference is fixed; individual fields mutate (e.g. focused).
Writing visible or disabled changes only what the next paint would draw — it does not ask for that paint. Follow such a write with invalidate (or invalidateLayout, which a visibility flip needs, since layout omits hidden views). A development build warns when a write goes unaccounted for.
Inherited from
undoStack
readonlyundoStack:UndoStack
Defined in: ui/src/editor/editor.ts:123
Inherited from
vBar
vBar:
GadgetBar|null=null
Defined in: ui/src/editor/editor.ts:133
Inherited from
Methods
accelerators()
accelerators(): readonly
string[]
Defined in: ui/src/view/view.ts:142
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
attachGadgets()
attachGadgets(
h?,v?,ind?):void
Defined in: ui/src/editor/editor.ts:233
Wire up the scroll bars and line/column indicator that display and drive this editor.
Parameters
h?
GadgetBar
v?
GadgetBar
ind?
Returns
void
Inherited from
bind()
bind<
T>(reader,apply?,opts?):void
Defined in: ui/src/view/view.ts:326
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 { View, signal, type DrawContext } from '@jsvision/ui';
const count = signal(0);
class StatusLine extends View {
draw(ctx: DrawContext): void {
ctx.text(0, 0, `${count()} pending`, ctx.color('statusBar'));
}
}
const status = new StatusLine();
// In onMount, not the constructor: bind() needs the view's scope, which only exists once mounted.
status.onMount(() => {
status.bind(() => count()); // repaint the status line whenever `count` changes
});Inherited from
copy()
copy():
void
Defined in: ui/src/editor/editor.ts:283
Copy the selection to the canonical clipboard and refresh any visible clipboard projection.
Returns
void
Inherited from
cut()
cut():
void
Defined in: ui/src/editor/editor.ts:288
Cut the selection to the canonical clipboard as one undo step.
Returns
void
Inherited from
deleteSelect()
deleteSelect():
void
Defined in: ui/src/editor/editor.ts:421
Returns
void
Inherited from
derived()
protectedderived<T>(fn): () =>T
Defined in: ui/src/view/view.ts:359
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/editor/editor.ts:241
The hardware-caret cell (view-local) while focused and in view, else null.
Returns
Point | null
Inherited from
doSearchReplace()
doSearchReplace():
Promise<number>
Defined in: ui/src/editor/editor.ts:278
Returns
Promise<number>
Inherited from
draw()
draw(
ctx):void
Defined in: ui/src/editor/editor.ts:491
Paint the visible rows.
Parameters
ctx
Returns
void
Inherited from
execute()
execute(
action):void
Defined in: ui/src/editor/editor.ts:228
Run one editor action programmatically — the same operations the keymap triggers.
Parameters
action
The action to run (e.g. 'lineDown', 'undo', 'textEnd', 'selectAll').
Returns
void
Example
import { Editor } from '@jsvision/ui';
const editor = new Editor();
editor.setText('hello world');
editor.execute('textEnd'); // caret to end of bufferInherited from
find()
find():
Promise<void>
Defined in: ui/src/editor/editor.ts:260
Open the Find dialog and search for the first match. Resolves when the interaction is done.
Returns
Promise<void>
Inherited from
focusSignal()
focusSignal():
Signal<void>
Defined in: ui/src/view/view.ts:183
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
import { View, Button, type DrawContext } from '@jsvision/ui';
// A caption that highlights while the control it labels holds focus.
class Caption extends View {
constructor(
private readonly text: string,
private readonly target: View,
) {
super();
// Reading the target's focus signal inside bind() ties this view's repaint to the target's
// focus flips — a view can observe focus it does not own.
this.onMount(() => this.bind(() => this.target.focusSignal()()));
}
draw(ctx: DrawContext): void {
ctx.text(0, 0, this.text, ctx.color(this.target.state.focused ? 'labelSelected' : 'label'));
}
}
const ok = new Button('~O~K');
const caption = new Caption('Confirm:', ok);Inherited from
getMousePtr()
getMousePtr(
local):number
Defined in: ui/src/editor/editor.ts:474
Parameters
local
Returns
number
Inherited from
getText()
getText(
range?):string
Defined in: ui/src/editor/editor.ts:199
The full buffer content, or the text in a [from, to) range — returned verbatim.
Parameters
range?
Optional half-open buffer-offset range; omit for the whole buffer.
from
number
to
number
Returns
string
The requested text.
Inherited from
insertText()
insertText(
text):void
Defined in: ui/src/editor/editor.ts:208
Insert text at the caret, replacing any selection; line endings are normalized to the buffer's kind, as if typed.
Parameters
text
string
The text to insert.
Returns
void
Inherited from
invalidate()
invalidate():
void
Defined in: ui/src/view/view.ts:244
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:250
Request a reflow (re-run layout, then repaint). Use this when a change affects size/position, not just pixels.
Returns
void
Inherited from
measure()?
optionalmeasure(available):Size2D
Defined in: ui/src/view/view.ts:90
Optional intrinsic-size hook for auto sizing — return the size this view wants for available.
Parameters
available
Returns
Inherited from
onCleanup()
onCleanup(
fn):void
Defined in: ui/src/view/view.ts:396
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/editor/editor.ts:496
Handle a dispatched event (keys, mouse/wheel, paste, and editing commands).
Parameters
ev
Returns
void
Inherited from
onMount()
onMount(
fn):void
Defined in: ui/src/view/view.ts:381
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
paste()
paste():
void
Defined in: ui/src/editor/editor.ts:293
Paste the canonical clipboard at the caret as one undo step.
Returns
void
Inherited from
redo()
redo():
void
Defined in: ui/src/editor/editor.ts:303
Redo the most recently undone edit.
Returns
void
Inherited from
replace()
replace():
Promise<number>
Defined in: ui/src/editor/editor.ts:265
Open the Replace dialog and run the replace loop; resolves with the number of replacements made.
Returns
Promise<number>
Inherited from
scrollTo()
scrollTo(
x,y):void
Defined in: ui/src/editor/editor.ts:465
Parameters
x
number
y
number
Returns
void
Inherited from
searchAgain()
searchAgain():
Promise<number>
Defined in: ui/src/editor/editor.ts:270
Repeat the last search/replace with the stored parameters; resolves with the replacement count.
Returns
Promise<number>
Inherited from
searchOnce()
searchOnce():
boolean
Defined in: ui/src/editor/editor.ts:274
Returns
boolean
Inherited from
selectByClick()?
optionalselectByClick():void
Defined in: ui/src/view/view.ts:229
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
selectionText()
selectionText():
string
Defined in: ui/src/editor/editor.ts:214
The currently selected text, or '' when there is no selection.
Returns
string
Inherited from
setLayout()
setLayout(
patch):void
Defined in: ui/src/view/view.ts:285
Change some of this view's layout props and request a reflow — the only way to write layout. Props the patch does not name are kept, and the reflow happens for you.
The merge is shallow, deliberately: size and rect are replaced whole rather than merged field-by-field. That is what makes a variant swap correct — going from {kind:'fixed',cells:1} to {kind:'fr',weight:1} must not leave a stale cells behind. The cost is that per-side padding cannot be patched one side at a time; pass the whole padding value.
Two behaviours worth knowing:
- An explicit
undefinedresets that prop to its layout default.setLayout({ size: undefined })makes the view auto-sized again, andsetLayout({ position: 'flow' })puts an absolutely-placed view back in the flow (its now-unusedrectis simply ignored). - Do not call it in a constructor of a class that subclasses may extend. A base constructor body runs before a subclass's
override readonly layout = {…}field initializer, and that initializer installs a fresh object, so the call would be erased. Call it after construction, or fromonMount.
Reflowing an unmounted view is a no-op, so calling it before mount is safe.
Parameters
patch
Partial<LayoutProps>
The layout props to change; anything omitted is preserved.
Returns
void
Example
import { Group } from '@jsvision/ui';
const panel = new Group();
panel.setLayout({ direction: 'col', padding: 1 });
// Later — `direction` and `padding` survive; once `panel` is mounted this also reflows:
panel.setLayout({ size: { kind: 'fr', weight: 1 } });Inherited from
setText()
setText(
text):void
Defined in: ui/src/editor/editor.ts:173
Replace the entire content (verbatim, mixed line endings preserved); the line-ending kind is re-detected and cursor/selection/scroll/undo history are reset.
Parameters
text
string
The new buffer content.
Returns
void
Inherited from
toggleInsMode()
toggleInsMode():
void
Defined in: ui/src/editor/editor.ts:459
Returns
void
Inherited from
undo()
undo():
void
Defined in: ui/src/editor/editor.ts:298
Undo the most recent edit.
Returns
void
Inherited from
viewH()
viewH():
number
Defined in: ui/src/editor/editor.ts:313
Returns
number