69 lines
1.8 KiB
JavaScript
69 lines
1.8 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @providesModule NativeEventEmitter
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* @flow
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*/
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'use strict';
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const EventEmitter = require('EventEmitter');
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const Platform = require('Platform');
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const RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
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const invariant = require('fbjs/lib/invariant');
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import type EmitterSubscription from 'EmitterSubscription';
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type NativeModule = {
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+addListener: (eventType: string) => void,
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+removeListeners: (count: number) => void,
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};
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/**
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* Abstract base class for implementing event-emitting modules. This implements
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* a subset of the standard EventEmitter node module API.
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*/
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class NativeEventEmitter extends EventEmitter {
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_nativeModule: ?NativeModule;
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constructor(nativeModule: ?NativeModule) {
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super(RCTDeviceEventEmitter.sharedSubscriber);
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if (Platform.OS === 'ios') {
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invariant(nativeModule, 'Native module cannot be null.');
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this._nativeModule = nativeModule;
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}
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}
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addListener(
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eventType: string,
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listener: Function,
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context: ?Object,
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): EmitterSubscription {
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if (this._nativeModule != null) {
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this._nativeModule.addListener(eventType);
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}
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return super.addListener(eventType, listener, context);
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}
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removeAllListeners(eventType: string) {
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invariant(eventType, 'eventType argument is required.');
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const count = this.listeners(eventType).length;
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if (this._nativeModule != null) {
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this._nativeModule.removeListeners(count);
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}
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super.removeAllListeners(eventType);
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}
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removeSubscription(subscription: EmitterSubscription) {
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if (this._nativeModule != null) {
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this._nativeModule.removeListeners(1);
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}
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super.removeSubscription(subscription);
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}
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}
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module.exports = NativeEventEmitter;
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