84 lines
2.7 KiB
TypeScript
84 lines
2.7 KiB
TypeScript
/*
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Copyright 2017 New Vector Ltd
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import RoomViewStore from './stores/RoomViewStore';
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type Listener = (isActive: boolean) => void;
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/**
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* Consumes changes from the RoomViewStore and notifies specific things
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* about when the active room changes. Unlike listening for RoomViewStore
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* changes, you can subscribe to only changes relevant to a particular
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* room.
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*
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* TODO: If we introduce an observer for something else, factor out
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* the adding / removing of listeners & emitting into a common class.
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*/
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export class ActiveRoomObserver {
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private listeners: {[key: string]: Listener[]} = {};
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private _activeRoomId = RoomViewStore.getRoomId();
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private readonly roomStoreToken: string;
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constructor() {
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// TODO: We could self-destruct when the last listener goes away, or at least stop listening.
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this.roomStoreToken = RoomViewStore.addListener(this.onRoomViewStoreUpdate);
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}
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public get activeRoomId(): string {
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return this._activeRoomId;
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}
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public addListener(roomId, listener) {
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if (!this.listeners[roomId]) this.listeners[roomId] = [];
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this.listeners[roomId].push(listener);
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}
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public removeListener(roomId, listener) {
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if (this.listeners[roomId]) {
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const i = this.listeners[roomId].indexOf(listener);
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if (i > -1) {
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this.listeners[roomId].splice(i, 1);
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}
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} else {
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console.warn("Unregistering unrecognised listener (roomId=" + roomId + ")");
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}
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}
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private emit(roomId, isActive: boolean) {
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if (!this.listeners[roomId]) return;
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for (const l of this.listeners[roomId]) {
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l.call(null, isActive);
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}
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}
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private onRoomViewStoreUpdate = () => {
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// emit for the old room ID
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if (this._activeRoomId) this.emit(this._activeRoomId, false);
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// update our cache
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this._activeRoomId = RoomViewStore.getRoomId();
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// and emit for the new one
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if (this._activeRoomId) this.emit(this._activeRoomId, true);
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};
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}
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if (window.mxActiveRoomObserver === undefined) {
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window.mxActiveRoomObserver = new ActiveRoomObserver();
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}
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export default window.mxActiveRoomObserver;
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