65 lines
1.7 KiB
JavaScript
65 lines
1.7 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
"use strict";
|
|
|
|
ChromeUtils.import("resource://normandy/lib/LogManager.jsm");
|
|
|
|
var EXPORTED_SYMBOLS = ["EventEmitter"];
|
|
|
|
const log = LogManager.getLogger("event-emitter");
|
|
|
|
var EventEmitter = function(sandboxManager) {
|
|
const listeners = {};
|
|
|
|
return {
|
|
createSandboxedEmitter() {
|
|
return sandboxManager.cloneInto({
|
|
on: this.on.bind(this),
|
|
off: this.off.bind(this),
|
|
once: this.once.bind(this),
|
|
}, {cloneFunctions: true});
|
|
},
|
|
|
|
emit(eventName, event) {
|
|
// Fire events async
|
|
Promise.resolve()
|
|
.then(() => {
|
|
if (!(eventName in listeners)) {
|
|
log.debug(`EventEmitter: Event fired with no listeners: ${eventName}`);
|
|
return;
|
|
}
|
|
// Clone callbacks array to avoid problems with mutation while iterating
|
|
const callbacks = Array.from(listeners[eventName]);
|
|
for (const cb of callbacks) {
|
|
cb(sandboxManager.cloneInto(event));
|
|
}
|
|
});
|
|
},
|
|
|
|
on(eventName, callback) {
|
|
if (!(eventName in listeners)) {
|
|
listeners[eventName] = [];
|
|
}
|
|
listeners[eventName].push(callback);
|
|
},
|
|
|
|
off(eventName, callback) {
|
|
if (eventName in listeners) {
|
|
const index = listeners[eventName].indexOf(callback);
|
|
if (index !== -1) {
|
|
listeners[eventName].splice(index, 1);
|
|
}
|
|
}
|
|
},
|
|
|
|
once(eventName, callback) {
|
|
const inner = event => {
|
|
callback(event);
|
|
this.off(eventName, inner);
|
|
};
|
|
this.on(eventName, inner);
|
|
},
|
|
};
|
|
};
|