element-web/src/ActiveRoomObserver.js
2018-12-13 13:02:35 +01:00

81 lines
2.8 KiB
JavaScript

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