73 lines
2.2 KiB
JavaScript
73 lines
2.2 KiB
JavaScript
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/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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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 NativeModules = require('NativeModules');
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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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/**
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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 {
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_listenerCount: number;
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_nativeModule: Object;
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constructor(nativeModuleName: string) {
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if (Platform.OS === 'ios') {
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this._listenerCount = 0;
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this._nativeModule = NativeModules[nativeModuleName];
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invariant(this._nativeModule,
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'Native module `' + nativeModuleName + '` not found.');
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}
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}
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addListener(eventType: string, listener: any, context: ?Object): EmitterSubscription {
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if (Platform.OS === 'ios') {
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this._listenerCount++;
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this._nativeModule.addListener(eventType);
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}
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return RCTDeviceEventEmitter.nativeAddListener(eventType, listener, context);
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}
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once(eventType: string, listener: any, context: ?Object): EmitterSubscription {
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return this.addListener(eventType, () => {
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this.removeCurrentListener();
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listener.apply(context, arguments);
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});
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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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if (Platform.OS === 'ios') {
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var count = RCTDeviceEventEmitter.listeners(eventType).length;
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this._nativeModule.removeListeners(count);
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}
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RCTDeviceEventEmitter.removeAllListeners(eventType);
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}
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removeCurrentListener() {
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if (Platform.OS === 'ios') {
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this._listenerCount--;
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this._nativeModule.removeListeners(1);
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}
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RCTDeviceEventEmitter.removeCurrentListener();
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}
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}
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module.exports = NativeEventEmitter;
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