Function invoker

packages/runtime-dom/src/modules/events.ts:99–148

(e: Event & { _vts?: number })

  instance: ComponentInternalInstance | null,
) {
  const invoker: Invoker = (e: Event & { _vts?: number }) => {
    // async edge case vuejs/vue#6566
    // inner click event triggers patch, event handler
    // attached to outer element during patch, and triggered again. This
    // happens because browsers fire microtask ticks between event propagation.
    // this no longer happens for templates in Vue 3, but could still be
    // theoretically possible for hand-written render functions.
    // the solution: we save the timestamp when a handler is attached,
    // and also attach the timestamp to any event that was handled by vue
    // for the first time (to avoid inconsistent event timestamp implementations
    // or events fired from iframes, e.g. #2513)
    // The handler would only fire if the event passed to it was fired
    // AFTER it was attached.
    if (!e._vts) {
      e._vts = Date.now()
    } else if (e._vts <= invoker.attached) {
      return
    }
    const value = invoker.value
    if (isArray(value)) {
      const originalStop = e.stopImmediatePropagation
      e.stopImmediatePropagation = () => {
        originalStop.call(e)
        ;(e as any)._stopped = true
      }
      const handlers = value.slice()
      const args = [e]
      for (let i = 0; i < handlers.length; i++) {
        if ((e as any)._stopped) {
          break
        }
        const handler = handlers[i]
        if (handler) {
          callWithAsyncErrorHandling(
            handler,
            instance,
            ErrorCodes.NATIVE_EVENT_HANDLER,
            args,
          )
        }
      }
    } else {
      callWithAsyncErrorHandling(
        value,
        instance,
        ErrorCodes.NATIVE_EVENT_HANDLER,
        [e],
      )
    }
  }
  invoker.value = initialValue
  invoker.attached = getNow()
  return invoker