rx-player
Version:
Canal+ HTML5 Video Player
106 lines (105 loc) • 3.78 kB
JavaScript
/**
* Copyright 2015 CANAL+ Group
*
* 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 isNullOrUndefined from "./is_null_or_undefined";
/**
* Simple but fully type-safe EventEmitter implementation.
* @class EventEmitter
*/
export default class EventEmitter {
constructor() {
this._listeners = {};
}
/**
* Register a new callback for an event.
*
* @param {string} evt - The event to register a callback to
* @param {Function} fn - The callback to call as that event is triggered.
* The callback will take as argument the eventual payload of the event
* (single argument).
* @param {Object | undefined} cancellationSignal - When that signal emits,
* the event listener is automatically removed.
*/
addEventListener(evt, fn, cancellationSignal) {
const listeners = this._listeners[evt];
if (!Array.isArray(listeners)) {
this._listeners[evt] = [fn];
}
else {
listeners.push(fn);
}
if (cancellationSignal !== undefined) {
cancellationSignal.register(() => {
this.removeEventListener(evt, fn);
});
}
}
/**
* Unregister callbacks linked to events.
* @param {string} [evt] - The event for which the callback[s] should be
* unregistered. Set it to null or undefined to remove all callbacks
* currently registered (for any event).
* @param {Function} [fn] - The callback to unregister. If set to null
* or undefined while the evt argument is set, all callbacks linked to that
* event will be unregistered.
*/
removeEventListener(evt, fn) {
if (isNullOrUndefined(evt)) {
this._listeners = {};
return;
}
const listeners = this._listeners[evt];
if (!Array.isArray(listeners)) {
return;
}
if (isNullOrUndefined(fn)) {
delete this._listeners[evt];
return;
}
const index = listeners.indexOf(fn);
if (index !== -1) {
listeners.splice(index, 1);
}
if (listeners.length === 0) {
delete this._listeners[evt];
}
}
/**
* Trigger every registered callbacks for a given event
* @param {string} evt - The event to trigger
* @param {*} arg - The eventual payload for that event. All triggered
* callbacks will recieve this payload as argument.
*/
trigger(evt, arg) {
const listeners = this._listeners[evt];
if (!Array.isArray(listeners)) {
return;
}
listeners.slice().forEach((listener) => {
try {
listener(arg);
}
catch (e) {
if (0 /* __ENVIRONMENT__.CURRENT_ENV */ === 1 /* __ENVIRONMENT__.DEV */) {
throw e instanceof Error ? e : new Error("EventEmitter: listener error");
}
// Cannot use our logger here sadly because our logger is an `EventEmitter`
// itself.
// eslint-disable-next-line no-console
console.error("RxPlayer: EventEmitter error", e instanceof Error ? e : null);
}
});
}
}