react-native/Libraries/Utilities/SceneTracker.js

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/**
* 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 SceneTracker
* @flow
*/
'use strict';
type Scene = {name: string};
let _listeners: Array<(scene: Scene) => void> = [];
let _activeScene = {name: 'default'};
const SceneTracker = {
setActiveScene(scene: Scene) {
_activeScene = scene;
_listeners.forEach((listener) => listener(_activeScene));
},
getActiveScene(): Scene {
return _activeScene;
},
addActiveSceneChangedListener(callback: (scene: Scene) => void): {remove: () => void} {
_listeners.push(callback);
return {
remove: () => {
_listeners = _listeners.filter((listener) => callback !== listener);
},
};
},
};
module.exports = SceneTracker;