manyfold/app/javascript/src/comlink_event_handler.ts

import * as Comlink from 'comlink'

interface UnifiedEvent {
  type: string
  altKey?: boolean
  ctrlKey?: boolean
  metaKey?: boolean
  shiftKey?: boolean
  button?: number
  buttons?: number
  clientX?: number
  clientY?: number
  pageX?: number
  pageY?: number
  pointerType?: string
  deltaX?: number
  deltaY?: number
  keyCode?: number
  code?: string
}

const handler: Comlink.TransferHandler<Event, UnifiedEvent> = {
  canHandle: (obj): obj is Event => (obj instanceof Event),
  serialize: (ev: Event) => {
    let serializedEvent: UnifiedEvent = { type: ev.type }
    if (ev instanceof PointerEvent) {
      serializedEvent = {
        altKey: ev.altKey,
        ctrlKey: ev.ctrlKey,
        metaKey: ev.metaKey,
        shiftKey: ev.shiftKey,
        button: ev.button,
        buttons: ev.buttons,
        clientX: ev.clientX,
        clientY: ev.clientY,
        pageX: ev.pageX,
        pageY: ev.pageY,
        pointerType: ev.pointerType,
        ...serializedEvent
      }
    }
    if (ev instanceof WheelEvent) {
      serializedEvent = {
        deltaX: ev.deltaX,
        deltaY: ev.deltaY,
        ...serializedEvent
      }
    }
    if (ev instanceof KeyboardEvent) {
      serializedEvent = {
        altKey: ev.altKey,
        ctrlKey: ev.ctrlKey,
        metaKey: ev.metaKey,
        shiftKey: ev.shiftKey,
        keyCode: ev.keyCode,
        code: ev.code,
        ...serializedEvent
      }
    }
    return [serializedEvent, []]
  },
  deserialize: (obj) => obj as Event
}

Comlink.transferHandlers.set('EVENT', handler)