jiti-meet/react/features/mobile/back-button/BackButtonRegistry.js

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2019-07-11 11:32:17 +00:00
// @flow
/**
* An registry that dispatches hardware back button events for subscribers with a custom logic.
*/
class BackButtonRegistry {
_listeners: Array<Function>;
/**
* Instantiates a new instance of the registry.
*/
constructor() {
this._listeners = [];
}
/**
* Adds a listener to the registry.
*
* NOTE: Due to the different order of component mounts, we allow a component to register
* its listener to the top of the list, so then that will be invoked before other, 'non-top'
* listeners. For example a 'non-top' listener can be the one that puts the app into PiP mode,
* while a 'top' listener is the one that closes a modal in a conference.
*
* @param {Function} listener - The listener function.
* @param {boolean?} top - If true, the listener will be put on the top (eg for modal-like components).
* @returns {void}
*/
addListener(listener: Function, top: boolean = false) {
if (top) {
this._listeners.splice(0, 0, listener);
} else {
this._listeners.push(listener);
}
}
/**
* Removes a listener from the registry.
*
* @param {Function} listener - The listener to remove.
* @returns {void}
*/
removeListener(listener: Function) {
this._listeners = this._listeners.filter(f => f !== listener);
}
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onHardwareBackPress: () => boolean;
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/**
* Callback for the back button press event.
*
* @returns {boolean}
*/
onHardwareBackPress() {
for (const listener of this._listeners) {
const result = listener();
if (result === true) {
return true;
}
}
return false;
}
}
export default new BackButtonRegistry();