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/* 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/. */
// Simple event emitter abstraction for storage objects to use.
export function EventEmitter() {
this._events = new Map();
}
EventEmitter.prototype = {
on(event, listener) {
if (this._events.has(event)) {
this._events.get(event).add(listener);
} else {
this._events.set(event, new Set([listener]));
}
},
off(event, listener) {
if (!this._events.has(event)) {
return;
}
this._events.get(event).delete(listener);
},
emit(event, ...args) {
if (!this._events.has(event)) {
return;
}
for (let listener of this._events.get(event).values()) {
try {
listener.apply(this, args);
} catch (e) {
console.error(e);
}
}
},
};
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