text: /**
   * Copyright (c) 2015-present, Facebook, Inc.
   *
   * This source code is licensed under the MIT license found in the
   * LICENSE file in the root directory of this source tree.
   *
   * @providesModule EmitterSubscription
   * @flow
   */
  'use strict';
  
  const EventSubscription = require('EventSubscription');
  
  import type EventEmitter from 'EventEmitter';
  import type EventSubscriptionVendor from 'EventSubscriptionVendor';
  
  /**
   * EmitterSubscription represents a subscription with listener and context data.
   */
  class EmitterSubscription extends EventSubscription {
  
    emitter: EventEmitter;
    listener: Function;
    context: ?Object;
  
    /**
     * @param {EventEmitter} emitter - The event emitter that registered this
     *   subscription
     * @param {EventSubscriptionVendor} subscriber - The subscriber that controls
     *   this subscription
     * @param {function} listener - Function to invoke when the specified event is
     *   emitted
     * @param {*} context - Optional context object to use when invoking the
     *   listener
     */
    constructor(
      emitter: EventEmitter,
      subscriber: EventSubscriptionVendor,
      listener: Function,
      context: ?Object
    ) {
      super(subscriber);
      this.emitter = emitter;
      this.listener = listener;
      this.context = context;
    }
  
    /**
     * Removes this subscription from the emitter that registered it.
     * Note: we're overriding the `remove()` method of EventSubscription here
     * but deliberately not calling `super.remove()` as the responsibility
     * for removing the subscription lies with the EventEmitter.
     */
    remove() {
      this.emitter.removeSubscription(this);
    }
  }
  
  module.exports = EmitterSubscription;
  