Browser API reference

Use this page to look up every option and method of the browser packages: @canvist/web and its /fonts, /menus, and /collab entry points, @canvist/headless/ssr, and @canvist/canvas. Each one also carries these descriptions in its TypeScript declarations, so your editor shows them on hover.

API stability

The browser packages follow semantic versioning with the rest of the SDK. Every change ships with a changeset that says what changed, and the changelog lists them. Until 1.0, a release that breaks an API raises the minor version (0.1 to 0.2) and says so under “Breaking Change”. Members marked @internal in the declarations aren’t part of the API and can change in any release.

`createEditor(element, options)`

From @canvist/web. It returns a promise of an Editor. @canvist/web/collab exports a createEditor with the same options, and its editors can collaborate.

Option	Type	Default	What it does
`extensions`	`ExtensionDescriptor[]`	TipTap’s StarterKit	The extensions to register. Commands, queries, and document JSON are typed from them.
`plugins`	`Plugin[]`	`[]`	Plugins such as `fonts()` from `@canvist/web/fonts`. Their APIs are on `editor.plugins`.
`content`	`{ format, input }` or ProseMirror JSON	the element’s HTML	The starting document. Without it, the editor reads server-rendered `.cv-doc` HTML inside the element, or starts empty.
`theme`	`ThemeOptions`	StarterKit light	`scheme`, `bodyFamily`, `codeFamily`, `size`, `lineHeight`, and `letterSpacing`. Server rendering must use the same one.
`editable`	`boolean`	`true`	`false` makes the editor read-only: selecting and copying still work, and commands still apply.
`placeholder`	`string`	`""`	Dimmed text where the first line starts while the document is empty. It’s also the field’s `aria-placeholder`.
`label`	`string`	`"Editor"`	The editor’s accessible name.
`input`	`"auto"`, `"editcontext"`, `"textarea"`	`"auto"`	How text arrives: `EditContext` where the browser has it, or a hidden textarea. `"textarea"` is the kill switch for EditContext problems.
`platform`	`"apple"`, `"other"`	detected	Whether `Mod` in key bindings is Cmd or Ctrl.
`breaks`	`"chromium"`, `"icu"`	detected	Which line-breaking tailoring layout follows, to match the browser’s own.
`client`	`number`	`1`	The client id new blocks are allocated under.
`overscan`	`number`	one screen	Pixels beyond the viewport to lay out ahead of scrolling.
`wasm`	`WasmSource`	next to the module	Where to load the WebAssembly module from: bytes, a compiled module, a URL, or a response.

`Editor`

Member	What it does
`commands.<name>(args)`, `can.<name>(args)`	Run a registered command, or check whether it would apply. Both return `boolean`.
`query.<name>(args)`	Answer a registered query.
`run(name, args)`, `ask(name, args)`	The same, for names picked at runtime.
`select(anchor, head?)`, `selection`	Set or read the selection. Positions are `{ path, offset }`, with offsets in UTF-16 code units.
`insertText(text)`, `undo()`, `redo()`	Type, undo, and redo, as the keyboard does. A shared editor undoes only its own changes.
`setContent(content)`, `export(format)`, `toJson()`	Replace the document, or read it as `json`, `html`, `markdown`, or `text`.
`toHtml()`, `toSvg()`	Server-rendered HTML and CSS at the editor’s width, or an SVG of the whole document.
`editable`, `setEditable(editable)`	Read or change read-only mode.
`setPlaceholder(text)`, `isEmpty`	Change the placeholder, or check for an empty document.
`focus()`, `focused`	Focus the editor without scrolling, or check whether it has focus.
`subscribe(listener)`	Call back after every change to the document, the selection, focus, or `editable`. Returns an unsubscribe function.
`caretRect()`, `selectionRect()`, `toClientRect(rect)`	The caret’s or selection’s rectangle in document coordinates, and conversion to viewport coordinates.
`blockText()`	The text of the block holding the selection’s head.
`ready()`, `hydrating`	Wait until fonts and plugins have settled and the canvas shows, or check whether server HTML still stands in.
`inputLatency()`, `stats()`, `fonts()`, `geometry()`	Input-to-paint times, measurement cache statistics, used fonts, and laid-out geometry.
`render()`, `destroy()`	Paint now, or remove the editor and release its memory.

`@canvist/web/menus`

bubbleMenu(editor, element, options) keeps element over selected text, and floatingMenu(editor, element, options) keeps it beside the caret on an empty line. Both return a Menu with visible, update(), and destroy().

Option	Type	Default	What it does
`placement`	`"top"`, `"bottom"`, `"left"`, `"right"`	`"top"` (bubble), `"left"` (floating)	The preferred side. The menu flips when there’s no room.
`offset`	`number`	`8`	The gap between the menu and the selection, in CSS pixels.
`padding`	`number`	`8`	The least distance from the viewport’s edges.
`shouldShow`	`(editor) => boolean`	see each function	Replaces the default rule for when the menu shows.

placeMenu(element, rect, { placement, offset, padding }) does the positioning on its own.

`@canvist/web/collab`

connect(editor, options) joins an editor from this module’s createEditor to a room, and returns a Connection. The connection has status ("connecting", "connected", or "disconnected"), synced, clientId, subscribe(listener), whenSynced(), and disconnect().

Option	Type	Default	What it does
`url`	`string`	(required)	The y-websocket server’s URL. The room is added as a path.
`room`	`string`	(required)	Every peer in a room edits one document.
`params`	`Record<string, string>`	none	Query parameters, such as a short-lived token.
`clientId`	`number`	random	This peer’s Yjs client id, unique in the room.
`reconnect`	`boolean`	`true`	Reconnect with backoff when the connection drops.
`WebSocket`	`typeof WebSocket`	the global	The `WebSocket` class to use.

`@canvist/headless/ssr`

createRenderer({ extensions, theme, fonts, wasm }) returns a Renderer: html(content, { width }) returns { html, css }, page(content, { width }) returns a complete page, svg(content, { width }) returns an SVG, and registerFont(bytes) adds a font for SVG text. fonts are TrueType or OpenType files. See Server-side rendering.

`@canvist/canvas`

mountCanvas(canvas, options) returns a CanvasHandle with backend, tools, setTool(name), tool(), toJson(), encodeState(), applyUpdate(update), frameTimes(), requestFrame(), and destroy().

Option	Type	Default	What it does
`scene`	`SceneJson`	one empty page	The starting scene. Give every peer in a room the same one.
`demo`	`boolean`	`false`	Start from canvist’s demo scene instead.
`transport`	`Transport`	none	Where collaboration messages go, such as `BroadcastTransport`.
`preferGpu`	`boolean`	`true`	Use WebGPU where the browser has it.
`wasmUrl`	`URL` or `string`	next to the module	Where the WebAssembly module is.
`onChange`	`(handle) => void`	none	Called after the canvas changes, for toolbars.
`stress`	`number`	`0`	Extra rectangles, for measuring frame times.