Function patchEventTargetMethods

packages/zone.js/lib/common/events.ts:305–897

(obj: any, patchOptions?: PatchEventTargetOptions)

  };

  function patchEventTargetMethods(obj: any, patchOptions?: PatchEventTargetOptions) {
    if (!obj) {
      return false;
    }

    let useGlobalCallback = true;
    if (patchOptions && patchOptions.useG !== undefined) {
      useGlobalCallback = patchOptions.useG;
    }
    const validateHandler = patchOptions && patchOptions.vh;

    let checkDuplicate = true;
    if (patchOptions && patchOptions.chkDup !== undefined) {
      checkDuplicate = patchOptions.chkDup;
    }

    let returnTarget = false;
    if (patchOptions && patchOptions.rt !== undefined) {
      returnTarget = patchOptions.rt;
    }

    let proto = obj;
    while (proto && !proto.hasOwnProperty(ADD_EVENT_LISTENER)) {
      proto = ObjectGetPrototypeOf(proto);
    }
    if (!proto && obj[ADD_EVENT_LISTENER]) {
      // somehow we did not find it, but we can see it. This happens on IE for Window properties.
      proto = obj;
    }

    if (!proto) {
      return false;
    }
    if (proto[zoneSymbolAddEventListener]) {
      return false;
    }

    const eventNameToString = patchOptions && patchOptions.eventNameToString;

    // We use a shared global `taskData` to pass data for `scheduleEventTask`,
    // eliminating the need to create a new object solely for passing data.
    // WARNING: This object has a static lifetime, meaning it is not created
    // each time `addEventListener` is called. It is instantiated only once
    // and captured by reference inside the `addEventListener` and
    // `removeEventListener` functions. Do not add any new properties to this
    // object, as doing so would necessitate maintaining the information
    // between `addEventListener` calls.
    const taskData: InternalGlobalTaskData = {};

    const nativeAddEventListener = (proto[zoneSymbolAddEventListener] = proto[ADD_EVENT_LISTENER]);
    const nativeRemoveEventListener = (proto[zoneSymbol(REMOVE_EVENT_LISTENER)] =
      proto[REMOVE_EVENT_LISTENER]);

    const nativeListeners = (proto[zoneSymbol(LISTENERS_EVENT_LISTENER)] =
      proto[LISTENERS_EVENT_LISTENER]);
    const nativeRemoveAllListeners = (proto[zoneSymbol(REMOVE_ALL_LISTENERS_EVENT_LISTENER)] =
      proto[REMOVE_ALL_LISTENERS_EVENT_LISTENER]);