react-native/Libraries/EventEmitter/EmitterSubscription.js

63 lines
1.8 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule EmitterSubscription
* @noflow
* @typechecks
*/
'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;