Internal Systems

EventBus (core/src/core/event/eventbus/EventBus.ts)

Typed pub/sub system for internal communication between editor modules.

eventBus.on('contentChange', handler)   // subscribe
eventBus.emit('contentChange', payload) // publish
eventBus.off('contentChange', handler)  // unsubscribe
eventBus.isSubscribe('contentChange')   // check if anyone is listening
eventBus.dangerouslyClearAll()          // wipe all subscriptions (called in destroy())

EventBus vs Listener

	EventBus	Listener
Audience	Internal modules	External users
Usage	Inter-module communication	User-facing callbacks
Example	Draw emits 'input' → Command reacts	editor.listener.contentChange = () => {}

Flow example:

User types
    ↓
CanvasEvent → eventBus.emit('input')
    ↓
Draw reacts → re-renders canvas
    ↓
Draw → eventBus.emit('contentChange')
    ↓
Listener.contentChange() fires → user's onChange callback

Available events (core/src/interface/EventBus.ts)

rangeStyleChange, visiblePageNoListChange, intersectionPageNoChange, pageSizeChange, pageScaleChange, saved, contentChange, controlChange, controlContentChange, pageModeChange, zoneChange, mousemove, mouseleave, mouseenter, mousedown, mouseup, click, input, positionContextChange, imageSizeChange, imageMousedown, imageDblclick, labelMousedown

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Listener (core/src/core/listener/Listener.ts)

Public callback hooks assigned directly by the user (or React wrapper):

editor.listener.contentChange = async () => { ... }
editor.listener.rangeStyleChange = (payload) => { ... }
editor.listener.pageSizeChange = (payload) => { ... }
editor.listener.visiblePageNoListChange = (payload) => { ... }
editor.listener.intersectionPageNoChange = (payload) => { ... }
editor.listener.pageScaleChange = (payload) => { ... }

In @windoc/react, these are wired automatically from props (onChange, onRangeStyleChange, etc.) inside useEffect.

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Override (core/src/core/override/Override.ts)

Lets users replace default behavior for 3 browser events:

editor.override.paste = (evt: ClipboardEvent) => {
  // Custom paste logic
  // Return { preventDefault: true } to stop default behavior
}

editor.override.copy = () => { ... }

editor.override.drop = (evt: DragEvent) => { ... }

All 3 are undefined by default — editor uses built-in behavior unless assigned.

Use case: Sanitizing pasted HTML, custom drag-drop file handling, etc.

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version (core/src/version.ts)

export const version = '0.3.3'

Must stay in sync with core/package.json. Always run yarn sync-version after bumping versions — this script now automatically updates version.ts alongside docs and README.

Accessible at runtime via editor.version.