TypeScript utils.Signals類代碼示例

  interactions.signals.on('down', ({ interaction, pointer, event, eventTarget, pointerIndex }) => {
    const timer = interaction.pointers[pointerIndex].hold
    const path = utils.dom.getPath(eventTarget)
    const signalArg = {
      interaction,
      pointer,
      event,
      eventTarget,
      type: 'hold',
      targets: [] as EventTargetList,
      path,
      element: null,
    }

    for (const element of path) {
      signalArg.element = element

      signals.fire('collect-targets', signalArg)
    }

    if (!signalArg.targets.length) { return }

    let minDuration = Infinity

    for (const target of signalArg.targets) {
      const holdDuration = target.eventable.options.holdDuration

      if (holdDuration < minDuration) {
        minDuration = holdDuration
      }
    }

    timer.duration = minDuration
    timer.timeout = setTimeout(() => {
      fire({
        interaction,
        eventTarget,
        pointer,
        event,
        type: 'hold',
      }, scope)
    }, minDuration)
  })

function collectEventTargets<T extends string> ({ interaction, pointer, event, eventTarget, type }: {
  interaction: Interaction,
  pointer: Interact.PointerType,
  event: Interact.PointerEventType,
  eventTarget: Interact.EventTarget,
  type: T
}) {
  const pointerIndex = interaction.getPointerIndex(pointer)
  const pointerInfo = interaction.pointers[pointerIndex]

  // do not fire a tap event if the pointer was moved before being lifted
  if (type === 'tap' && (interaction.pointerWasMoved ||
      // or if the pointerup target is different to the pointerdown target
      !(pointerInfo && pointerInfo.downTarget === eventTarget))) {
    return []
  }

  const path = utils.dom.getPath(eventTarget)
  const signalArg = {
    interaction,
    pointer,
    event,
    eventTarget,
    type,
    path,
    targets: [] as EventTargetList,
    element: null,
  }

  for (const element of path) {
    signalArg.element = element

    signals.fire('collect-targets', signalArg)
  }

  if (type === 'hold') {
    signalArg.targets = signalArg.targets.filter((target) =>
      target.eventable.options.holdDuration === interaction.pointers[pointerIndex].hold.duration)
  }

  return signalArg.targets
}

function fire<T extends string> (arg: {
  interaction: Interaction,
  pointer: Interact.PointerType,
  event: Interact.PointerEventType,
  eventTarget: Interact.EventTarget,
  targets?: EventTargetList,
  pointerEvent?: PointerEvent<T>,
  type: T
}, scope: Interact.Scope) {
  const {
    interaction, pointer, event, eventTarget,
    type = (arg as any).pointerEvent.type,
    targets = collectEventTargets(arg),
  } = arg

  const {
    pointerEvent = new PointerEvent(type, pointer, event, eventTarget, interaction, scope.now()),
  } = arg

  const signalArg = {
    interaction,
    pointer,
    event,
    eventTarget,
    targets,
    type,
    pointerEvent,
  }

  for (let i = 0; i < targets.length; i++) {
    const target = targets[i]

    for (const prop in target.props || {}) {
      (pointerEvent as any)[prop] = target.props[prop]
    }

    const origin = utils.getOriginXY(target.eventable, target.element)

    pointerEvent._subtractOrigin(origin)
    pointerEvent.eventable = target.eventable
    pointerEvent.currentTarget = target.element

    target.eventable.fire(pointerEvent)

    pointerEvent._addOrigin(origin)

    if (pointerEvent.immediatePropagationStopped ||
        (pointerEvent.propagationStopped &&
            (i + 1) < targets.length && targets[i + 1].element !== pointerEvent.currentTarget)) {
      break
    }
  }

  signals.fire('fired', signalArg)

  if (type === 'tap') {
    // if pointerEvent should make a double tap, create and fire a doubletap
    // PointerEvent and use that as the prevTap
    const prevTap = pointerEvent.double
      ? fire({
        interaction,
        pointer,
        event,
        eventTarget,
        type: 'doubletap',
      }, scope)
      : pointerEvent

    interaction.prevTap = prevTap
    interaction.tapTime = prevTap.timeStamp
  }

  return pointerEvent
}