javascript - 如何在 Chrome 中创建 TouchEvent？

Question

W3C specification声明 initTouchEvent 如下:

void initTouchEvent (in DOMString    type,
                     in boolean      canBubble,
                     in boolean      cancelable,
                     in AbstractView view,
                     in long         detail,
                     in boolean      ctrlKey,
                     in boolean      altKey,
                     in boolean      shiftKey,
                     in boolean      metaKey,
                     in TouchList    touches,
                     in TouchList    targetTouches,
                     in TouchList    changedTouches);

但是，当我在 Chrome 44 中尝试时:

var e = document.createEvent('TouchEvent');
e.initTouchEvent("touchstart", true, true, window, 1,
                 false, false, false, false, touches, null, null);

其中 touches 是一个有效的 TouchList，这是 Chrome 创建的:

> TouchEvent {}
    altKey: false
    bubbles: true
    cancelBubble: false
    cancelable: true
    changedTouches: null
    charCode: 0
    ctrlKey: true
    currentTarget: null
    defaultPrevented: false
    detail: 0
    eventPhase: 0
    keyCode: 0
    layerX: 0
    layerY: 0
    metaKey: false
    pageX: 0
    pageY: 0
    path: Array[0]
    returnValue: true
    shiftKey: false
    srcElement: null
    target: null
    targetTouches: null
    timeStamp: 1435339572699
    touches: null
    type: "[object Window]"
    view: null
    which: 0

仔细查看 type 字段。似乎 Chrome 没有遵循规范，其中第 4 个参数变成了类型而不是第一个参数。

这给我们带来了一个问题，即我如何在 Chrome 中实际创建一个 TouchEvent，因为它不符合规范？

Answer 1

通过查看 Chromium source和 Qiita (in Japanese) ，这似乎是它的参数排列方式:

initTouchEvent (TouchList touches,
                TouchList targetTouches,
                TouchList changedTouches,
                String type,
                Window view,
                number screenX,
                number screenY,
                number clientX,
                number clientY,
                boolean ctrlKey, 
                boolean altKey,
                boolean shiftKey,
                boolean metaKey);

注意 Chrome 不遵循 W3C 规范。

---

Chromium 源代码中的相关部分:

TouchEvent.cpp 第 63 行:

void TouchEvent::initTouchEvent(ScriptState* scriptState, TouchList* touches, TouchList* targetTouches,
        TouchList* changedTouches, const AtomicString& type,
        PassRefPtrWillBeRawPtr<AbstractView> view,
        int, int, int, int,
        bool ctrlKey, bool altKey, bool shiftKey, bool metaKey)
{
    if (dispatched())
        return;

    if (scriptState->world().isIsolatedWorld())
        UIEventWithKeyState::didCreateEventInIsolatedWorld(ctrlKey, altKey, shiftKey, metaKey);

    bool cancelable = true;
    if (type == EventTypeNames::touchcancel)
        cancelable = false;

    initUIEvent(type, true, cancelable, view, 0);

    m_touches = touches;
    m_targetTouches = targetTouches;
    m_changedTouches = changedTouches;
    m_ctrlKey = ctrlKey;
    m_altKey = altKey;
    m_shiftKey = shiftKey;
    m_metaKey = metaKey;
}