angular-cn/packages/zone.js/lib/common/events.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
/**
 * @fileoverview
 * @suppress {missingRequire}
 */

import {ADD_EVENT_LISTENER_STR, FALSE_STR, ObjectGetPrototypeOf, REMOVE_EVENT_LISTENER_STR, TRUE_STR, ZONE_SYMBOL_PREFIX, attachOriginToPatched, isNode, zoneSymbol} from './utils';


/** @internal **/
interface EventTaskData extends TaskData {
  // use global callback or not
  readonly useG?: boolean;
}

let passiveSupported = false;

if (typeof window !== 'undefined') {
  try {
    const options =
        Object.defineProperty({}, 'passive', {get: function() { passiveSupported = true; }});

    window.addEventListener('test', options, options);
    window.removeEventListener('test', options, options);
  } catch (err) {
    passiveSupported = false;
  }
}

// an identifier to tell ZoneTask do not create a new invoke closure
const OPTIMIZED_ZONE_EVENT_TASK_DATA: EventTaskData = {
  useG: true
};

export const zoneSymbolEventNames: any = {};
export const globalSources: any = {};

const EVENT_NAME_SYMBOL_REGX = new RegExp('^' + ZONE_SYMBOL_PREFIX + '(\\w+)(true|false)$');
const IMMEDIATE_PROPAGATION_SYMBOL = zoneSymbol('propagationStopped');

function prepareEventNames(eventName: string, eventNameToString?: (eventName: string) => string) {
  const falseEventName = (eventNameToString ? eventNameToString(eventName) : eventName) + FALSE_STR;
  const trueEventName = (eventNameToString ? eventNameToString(eventName) : eventName) + TRUE_STR;
  const symbol = ZONE_SYMBOL_PREFIX + falseEventName;
  const symbolCapture = ZONE_SYMBOL_PREFIX + trueEventName;
  zoneSymbolEventNames[eventName] = {};
  zoneSymbolEventNames[eventName][FALSE_STR] = symbol;
  zoneSymbolEventNames[eventName][TRUE_STR] = symbolCapture;
}

export interface PatchEventTargetOptions {
  // validateHandler
  vh?: (nativeDelegate: any, delegate: any, target: any, args: any) => boolean;
  // addEventListener function name
  add?: string;
  // removeEventListener function name
  rm?: string;
  // prependEventListener function name
  prepend?: string;
  // listeners function name
  listeners?: string;
  // removeAllListeners function name
  rmAll?: string;
  // useGlobalCallback flag
  useG?: boolean;
  // check duplicate flag when addEventListener
  chkDup?: boolean;
  // return target flag when addEventListener
  rt?: boolean;
  // event compare handler
  diff?: (task: any, delegate: any) => boolean;
  // support passive or not
  supportPassive?: boolean;
  // get string from eventName (in nodejs, eventName maybe Symbol)
  eventNameToString?: (eventName: any) => string;
  // transfer eventName
  transferEventName?: (eventName: string) => string;
}

export function patchEventTarget(
    _global: any, apis: any[], patchOptions?: PatchEventTargetOptions) {
  const ADD_EVENT_LISTENER = (patchOptions && patchOptions.add) || ADD_EVENT_LISTENER_STR;
  const REMOVE_EVENT_LISTENER = (patchOptions && patchOptions.rm) || REMOVE_EVENT_LISTENER_STR;

  const LISTENERS_EVENT_LISTENER = (patchOptions && patchOptions.listeners) || 'eventListeners';
  const REMOVE_ALL_LISTENERS_EVENT_LISTENER =
      (patchOptions && patchOptions.rmAll) || 'removeAllListeners';

  const zoneSymbolAddEventListener = zoneSymbol(ADD_EVENT_LISTENER);

  const ADD_EVENT_LISTENER_SOURCE = '.' + ADD_EVENT_LISTENER + ':';

  const PREPEND_EVENT_LISTENER = 'prependListener';
  const PREPEND_EVENT_LISTENER_SOURCE = '.' + PREPEND_EVENT_LISTENER + ':';

  const invokeTask = function(task: any, target: any, event: Event) {
    // for better performance, check isRemoved which is set
    // by removeEventListener
    if (task.isRemoved) {
      return;
    }
    const delegate = task.callback;
    if (typeof delegate === 'object' && delegate.handleEvent) {
      // create the bind version of handleEvent when invoke
      task.callback = (event: Event) => delegate.handleEvent(event);
      task.originalDelegate = delegate;
    }
    // invoke static task.invoke
    task.invoke(task, target, [event]);
    const options = task.options;
    if (options && typeof options === 'object' && options.once) {
      // if options.once is true, after invoke once remove listener here
      // only browser need to do this, nodejs eventEmitter will cal removeListener
      // inside EventEmitter.once
      const delegate = task.originalDelegate ? task.originalDelegate : task.callback;
      target[REMOVE_EVENT_LISTENER].call(target, event.type, delegate, options);
    }
  };

  // global shared zoneAwareCallback to handle all event callback with capture = false
  const globalZoneAwareCallback = function(this: unknown, event: Event) {
    // https://github.com/angular/zone.js/issues/911, in IE, sometimes
    // event will be undefined, so we need to use window.event
    event = event || _global.event;
    if (!event) {
      return;
    }
    // event.target is needed for Samsung TV and SourceBuffer
    // || global is needed https://github.com/angular/zone.js/issues/190
    const target: any = this || event.target || _global;
    const tasks = target[zoneSymbolEventNames[event.type][FALSE_STR]];
    if (tasks) {
      // invoke all tasks which attached to current target with given event.type and capture = false
      // for performance concern, if task.length === 1, just invoke
      if (tasks.length === 1) {
        invokeTask(tasks[0], target, event);
      } else {
        // https://github.com/angular/zone.js/issues/836
        // copy the tasks array before invoke, to avoid
        // the callback will remove itself or other listener
        const copyTasks = tasks.slice();
        for (let i = 0; i < copyTasks.length; i++) {
          if (event && (event as any)[IMMEDIATE_PROPAGATION_SYMBOL] === true) {
            break;
          }
          invokeTask(copyTasks[i], target, event);
        }
      }
    }
  };

  // global shared zoneAwareCallback to handle all event callback with capture = true
  const globalZoneAwareCaptureCallback = function(this: unknown, event: Event) {
    // https://github.com/angular/zone.js/issues/911, in IE, sometimes
    // event will be undefined, so we need to use window.event
    event = event || _global.event;
    if (!event) {
      return;
    }
    // event.target is needed for Samsung TV and SourceBuffer
    // || global is needed https://github.com/angular/zone.js/issues/190
    const target: any = this || event.target || _global;
    const tasks = target[zoneSymbolEventNames[event.type][TRUE_STR]];
    if (tasks) {
      // invoke all tasks which attached to current target with given event.type and capture = false
      // for performance concern, if task.length === 1, just invoke
      if (tasks.length === 1) {
        invokeTask(tasks[0], target, event);
      } else {
        // https://github.com/angular/zone.js/issues/836
        // copy the tasks array before invoke, to avoid
        // the callback will remove itself or other listener
        const copyTasks = tasks.slice();
        for (let i = 0; i < copyTasks.length; i++) {
          if (event && (event as any)[IMMEDIATE_PROPAGATION_SYMBOL] === true) {
            break;
          }
          invokeTask(copyTasks[i], target, event);
        }
      }
    }
  };

  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;

    // a shared global taskData to pass data for scheduleEventTask
    // so we do not need to create a new object just for pass some data
    const taskData: any = {};

    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];

    let nativePrependEventListener: any;
    if (patchOptions && patchOptions.prepend) {
      nativePrependEventListener = proto[zoneSymbol(patchOptions.prepend)] =
          proto[patchOptions.prepend];
    }

    function checkIsPassive(task: Task) {
      if (!passiveSupported && typeof taskData.options !== 'boolean' &&
          typeof taskData.options !== 'undefined' && taskData.options !== null) {
        // options is a non-null non-undefined object
        // passive is not supported
        // don't pass options as object
        // just pass capture as a boolean
        (task as any).options = !!taskData.options.capture;
        taskData.options = (task as any).options;
      }
    }

    /**
     *
     * this util function will build an option object with passive option
     * to handle all possible input from the user
     */
    function buildPassiveOptions(options: any, passive: boolean) {
      if (!passiveSupported || !passive) {
        return options;
      }
      if (!options) {
        return {passive: true};
      }
      if (typeof options === 'boolean') {
        return {capture: options, passive: true};
      }
      if (typeof options === 'object') {
        if (typeof options.passive === 'boolean' && !options.passive) {
          return options;
        }
        return {...options, passive: true};
      }
      return options;
    }

    const customScheduleGlobal = function(task: Task) {
      // if there is already a task for the eventName + capture,
      // just return, because we use the shared globalZoneAwareCallback here.
      if (taskData.isExisting) {
        return;
      }
      checkIsPassive(task);
      return nativeAddEventListener.call(
          taskData.target, taskData.eventName,
          taskData.capture ? globalZoneAwareCaptureCallback : globalZoneAwareCallback,
          taskData.options);
    };

    const customCancelGlobal = function(task: any) {
      // if task is not marked as isRemoved, this call is directly
      // from Zone.prototype.cancelTask, we should remove the task
      // from tasksList of target first
      if (!task.isRemoved) {
        const symbolEventNames = zoneSymbolEventNames[task.eventName];
        let symbolEventName;
        if (symbolEventNames) {
          symbolEventName = symbolEventNames[task.capture ? TRUE_STR : FALSE_STR];
        }
        const existingTasks = symbolEventName && task.target[symbolEventName];
        if (existingTasks) {
          for (let i = 0; i < existingTasks.length; i++) {
            const existingTask = existingTasks[i];
            if (existingTask === task) {
              existingTasks.splice(i, 1);
              // set isRemoved to data for faster invokeTask check
              task.isRemoved = true;
              if (existingTasks.length === 0) {
                // all tasks for the eventName + capture have gone,
                // remove globalZoneAwareCallback and remove the task cache from target
                task.allRemoved = true;
                task.target[symbolEventName] = null;
              }
              break;
            }
          }
        }
      }
      // if all tasks for the eventName + capture have gone,
      // we will really remove the global event callback,
      // if not, return
      if (!task.allRemoved) {
        return;
      }
      return nativeRemoveEventListener.call(
          task.target, task.eventName,
          task.capture ? globalZoneAwareCaptureCallback : globalZoneAwareCallback, task.options);
    };

    const customScheduleNonGlobal = function(task: Task) {
      checkIsPassive(task);
      return nativeAddEventListener.call(
          taskData.target, taskData.eventName, task.invoke, taskData.options);
    };

    const customSchedulePrepend = function(task: Task) {
      return nativePrependEventListener.call(
          taskData.target, taskData.eventName, task.invoke, taskData.options);
    };

    const customCancelNonGlobal = function(task: any) {
      return nativeRemoveEventListener.call(task.target, task.eventName, task.invoke, task.options);
    };

    const customSchedule = useGlobalCallback ? customScheduleGlobal : customScheduleNonGlobal;
    const customCancel = useGlobalCallback ? customCancelGlobal : customCancelNonGlobal;

    const compareTaskCallbackVsDelegate = function(task: any, delegate: any) {
      const typeOfDelegate = typeof delegate;
      return (typeOfDelegate === 'function' && task.callback === delegate) ||
          (typeOfDelegate === 'object' && task.originalDelegate === delegate);
    };

    const compare =
        (patchOptions && patchOptions.diff) ? patchOptions.diff : compareTaskCallbackVsDelegate;

    const blackListedEvents: string[] = (Zone as any)[zoneSymbol('BLACK_LISTED_EVENTS')];
    const passiveEvents: string[] = _global[zoneSymbol('PASSIVE_EVENTS')];

    const makeAddListener = function(
        nativeListener: any, addSource: string, customScheduleFn: any, customCancelFn: any,
        returnTarget = false, prepend = false) {
      return function(this: unknown) {
        const target = this || _global;
        let eventName = arguments[0];
        if (patchOptions && patchOptions.transferEventName) {
          eventName = patchOptions.transferEventName(eventName);
        }
        let delegate = arguments[1];
        if (!delegate) {
          return nativeListener.apply(this, arguments);
        }
        if (isNode && eventName === 'uncaughtException') {
          // don't patch uncaughtException of nodejs to prevent endless loop
          return nativeListener.apply(this, arguments);
        }

        // don't create the bind delegate function for handleEvent
        // case here to improve addEventListener performance
        // we will create the bind delegate when invoke
        let isHandleEvent = false;
        if (typeof delegate !== 'function') {
          if (!delegate.handleEvent) {
            return nativeListener.apply(this, arguments);
          }
          isHandleEvent = true;
        }

        if (validateHandler && !validateHandler(nativeListener, delegate, target, arguments)) {
          return;
        }

        const options = arguments[2];
        const passive =
            passiveSupported && !!passiveEvents && passiveEvents.indexOf(eventName) !== -1;

        if (blackListedEvents) {
          // check black list
          for (let i = 0; i < blackListedEvents.length; i++) {
            if (eventName === blackListedEvents[i]) {
              if (passive) {
                const passiveOptions = buildPassiveOptions(options, passive);
                return nativeListener.call(target, eventName, delegate, passiveOptions);
              } else {
                return nativeListener.apply(this, arguments);
              }
            }
          }
        }

        let capture;
        let once = false;
        if (options === undefined) {
          capture = false;
        } else if (options === true) {
          capture = true;
        } else if (options === false) {
          capture = false;
        } else {
          capture = options ? !!options.capture : false;
          once = options ? !!options.once : false;
        }

        const zone = Zone.current;
        let symbolEventNames = zoneSymbolEventNames[eventName];
        if (!symbolEventNames) {
          prepareEventNames(eventName, eventNameToString);
          symbolEventNames = zoneSymbolEventNames[eventName];
        }
        const symbolEventName = symbolEventNames[capture ? TRUE_STR : FALSE_STR];
        let existingTasks = target[symbolEventName];
        let isExisting = false;
        if (existingTasks) {
          // already have task registered
          isExisting = true;
          if (checkDuplicate) {
            for (let i = 0; i < existingTasks.length; i++) {
              if (compare(existingTasks[i], delegate)) {
                // same callback, same capture, same event name, just return
                return;
              }
            }
          }
        } else {
          existingTasks = target[symbolEventName] = [];
        }
        let source;
        const constructorName = target.constructor['name'];
        const targetSource = globalSources[constructorName];
        if (targetSource) {
          source = targetSource[eventName];
        }
        if (!source) {
          source = constructorName + addSource +
              (eventNameToString ? eventNameToString(eventName) : eventName);
        }
        // do not create a new object as task.data to pass those things
        // just use the global shared one
        taskData.options = buildPassiveOptions(options, passive);
        if (once) {
          // if addEventListener with once options, we don't pass it to
          // native addEventListener, instead we keep the once setting
          // and handle ourselves.
          taskData.options.once = false;
        }
        taskData.target = target;
        taskData.capture = capture;
        taskData.eventName = eventName;
        taskData.isExisting = isExisting;

        const data = useGlobalCallback ? OPTIMIZED_ZONE_EVENT_TASK_DATA : undefined;

        // keep taskData into data to allow onScheduleEventTask to access the task information
        if (data) {
          (data as any).taskData = taskData;
        }

        const task: any =
            zone.scheduleEventTask(source, delegate, data, customScheduleFn, customCancelFn);

        // should clear taskData.target to avoid memory leak
        // issue, https://github.com/angular/angular/issues/20442
        taskData.target = null;

        // need to clear up taskData because it is a global object
        if (data) {
          (data as any).taskData = null;
        }

        // have to save those information to task in case
        // application may call task.zone.cancelTask() directly
        if (once) {
          options.once = true;
        }
        if (!(!passiveSupported && typeof task.options === 'boolean')) {
          // if not support passive, and we pass an option object
          // to addEventListener, we should save the options to task
          task.options = options;
        }
        task.target = target;
        task.capture = capture;
        task.eventName = eventName;
        if (isHandleEvent) {
          // save original delegate for compare to check duplicate
          (task as any).originalDelegate = delegate;
        }
        if (!prepend) {
          existingTasks.push(task);
        } else {
          existingTasks.unshift(task);
        }

        if (returnTarget) {
          return target;
        }
      };
    };

    proto[ADD_EVENT_LISTENER] = makeAddListener(
        nativeAddEventListener, ADD_EVENT_LISTENER_SOURCE, customSchedule, customCancel,
        returnTarget);
    if (nativePrependEventListener) {
      proto[PREPEND_EVENT_LISTENER] = makeAddListener(
          nativePrependEventListener, PREPEND_EVENT_LISTENER_SOURCE, customSchedulePrepend,
          customCancel, returnTarget, true);
    }

    proto[REMOVE_EVENT_LISTENER] = function() {
      const target = this || _global;
      let eventName = arguments[0];
      if (patchOptions && patchOptions.transferEventName) {
        eventName = patchOptions.transferEventName(eventName);
      }
      const options = arguments[2];

      let capture;
      if (options === undefined) {
        capture = false;
      } else if (options === true) {
        capture = true;
      } else if (options === false) {
        capture = false;
      } else {
        capture = options ? !!options.capture : false;
      }

      const delegate = arguments[1];
      if (!delegate) {
        return nativeRemoveEventListener.apply(this, arguments);
      }

      if (validateHandler &&
          !validateHandler(nativeRemoveEventListener, delegate, target, arguments)) {
        return;
      }

      const symbolEventNames = zoneSymbolEventNames[eventName];
      let symbolEventName;
      if (symbolEventNames) {
        symbolEventName = symbolEventNames[capture ? TRUE_STR : FALSE_STR];
      }
      const existingTasks = symbolEventName && target[symbolEventName];
      if (existingTasks) {
        for (let i = 0; i < existingTasks.length; i++) {
          const existingTask = existingTasks[i];
          if (compare(existingTask, delegate)) {
            existingTasks.splice(i, 1);
            // set isRemoved to data for faster invokeTask check
            (existingTask as any).isRemoved = true;
            if (existingTasks.length === 0) {
              // all tasks for the eventName + capture have gone,
              // remove globalZoneAwareCallback and remove the task cache from target
              (existingTask as any).allRemoved = true;
              target[symbolEventName] = null;
              // in the target, we have an event listener which is added by on_property
              // such as target.onclick = function() {}, so we need to clear this internal
              // property too if all delegates all removed
              if (typeof eventName === 'string') {
                const onPropertySymbol = ZONE_SYMBOL_PREFIX + 'ON_PROPERTY' + eventName;
                target[onPropertySymbol] = null;
              }
            }
            existingTask.zone.cancelTask(existingTask);
            if (returnTarget) {
              return target;
            }
            return;
          }
        }
      }
      // issue 930, didn't find the event name or callback
      // from zone kept existingTasks, the callback maybe
      // added outside of zone, we need to call native removeEventListener
      // to try to remove it.
      return nativeRemoveEventListener.apply(this, arguments);
    };

    proto[LISTENERS_EVENT_LISTENER] = function() {
      const target = this || _global;
      let eventName = arguments[0];
      if (patchOptions && patchOptions.transferEventName) {
        eventName = patchOptions.transferEventName(eventName);
      }

      const listeners: any[] = [];
      const tasks =
          findEventTasks(target, eventNameToString ? eventNameToString(eventName) : eventName);

      for (let i = 0; i < tasks.length; i++) {
        const task: any = tasks[i];
        let delegate = task.originalDelegate ? task.originalDelegate : task.callback;
        listeners.push(delegate);
      }
      return listeners;
    };

    proto[REMOVE_ALL_LISTENERS_EVENT_LISTENER] = function() {
      const target = this || _global;

      let eventName = arguments[0];
      if (!eventName) {
        const keys = Object.keys(target);
        for (let i = 0; i < keys.length; i++) {
          const prop = keys[i];
          const match = EVENT_NAME_SYMBOL_REGX.exec(prop);
          let evtName = match && match[1];
          // in nodejs EventEmitter, removeListener event is
          // used for monitoring the removeListener call,
          // so just keep removeListener eventListener until
          // all other eventListeners are removed
          if (evtName && evtName !== 'removeListener') {
            this[REMOVE_ALL_LISTENERS_EVENT_LISTENER].call(this, evtName);
          }
        }
        // remove removeListener listener finally
        this[REMOVE_ALL_LISTENERS_EVENT_LISTENER].call(this, 'removeListener');
      } else {
        if (patchOptions && patchOptions.transferEventName) {
          eventName = patchOptions.transferEventName(eventName);
        }
        const symbolEventNames = zoneSymbolEventNames[eventName];
        if (symbolEventNames) {
          const symbolEventName = symbolEventNames[FALSE_STR];
          const symbolCaptureEventName = symbolEventNames[TRUE_STR];

          const tasks = target[symbolEventName];
          const captureTasks = target[symbolCaptureEventName];

          if (tasks) {
            const removeTasks = tasks.slice();
            for (let i = 0; i < removeTasks.length; i++) {
              const task = removeTasks[i];
              let delegate = task.originalDelegate ? task.originalDelegate : task.callback;
              this[REMOVE_EVENT_LISTENER].call(this, eventName, delegate, task.options);
            }
          }

          if (captureTasks) {
            const removeTasks = captureTasks.slice();
            for (let i = 0; i < removeTasks.length; i++) {
              const task = removeTasks[i];
              let delegate = task.originalDelegate ? task.originalDelegate : task.callback;
              this[REMOVE_EVENT_LISTENER].call(this, eventName, delegate, task.options);
            }
          }
        }
      }

      if (returnTarget) {
        return this;
      }
    };

    // for native toString patch
    attachOriginToPatched(proto[ADD_EVENT_LISTENER], nativeAddEventListener);
    attachOriginToPatched(proto[REMOVE_EVENT_LISTENER], nativeRemoveEventListener);
    if (nativeRemoveAllListeners) {
      attachOriginToPatched(proto[REMOVE_ALL_LISTENERS_EVENT_LISTENER], nativeRemoveAllListeners);
    }
    if (nativeListeners) {
      attachOriginToPatched(proto[LISTENERS_EVENT_LISTENER], nativeListeners);
    }
    return true;
  }

  let results: any[] = [];
  for (let i = 0; i < apis.length; i++) {
    results[i] = patchEventTargetMethods(apis[i], patchOptions);
  }

  return results;
}

export function findEventTasks(target: any, eventName: string): Task[] {
  if (!eventName) {
    const foundTasks: any[] = [];
    for (let prop in target) {
      const match = EVENT_NAME_SYMBOL_REGX.exec(prop);
      let evtName = match && match[1];
      if (evtName && (!eventName || evtName === eventName)) {
        const tasks: any = target[prop];
        if (tasks) {
          for (let i = 0; i < tasks.length; i++) {
            foundTasks.push(tasks[i]);
          }
        }
      }
    }
    return foundTasks;
  }
  let symbolEventName = zoneSymbolEventNames[eventName];
  if (!symbolEventName) {
    prepareEventNames(eventName);
    symbolEventName = zoneSymbolEventNames[eventName];
  }
  const captureFalseTasks = target[symbolEventName[FALSE_STR]];
  const captureTrueTasks = target[symbolEventName[TRUE_STR]];
  if (!captureFalseTasks) {
    return captureTrueTasks ? captureTrueTasks.slice() : [];
  } else {
    return captureTrueTasks ? captureFalseTasks.concat(captureTrueTasks) :
                              captureFalseTasks.slice();
  }
}

export function patchEventPrototype(global: any, api: _ZonePrivate) {
  const Event = global['Event'];
  if (Event && Event.prototype) {
    api.patchMethod(
        Event.prototype, 'stopImmediatePropagation',
        (delegate: Function) => function(self: any, args: any[]) {
          self[IMMEDIATE_PROPAGATION_SYMBOL] = true;
          // we need to call the native stopImmediatePropagation
          // in case in some hybrid application, some part of
          // application will be controlled by zone, some are not
          delegate && delegate.apply(self, args);
        });
  }
}