tone
Version:
A Web Audio framework for making interactive music in the browser.
113 lines • 3.73 kB
JavaScript
import { Tone } from "../Tone.js";
import { isUndef } from "./TypeCheck.js";
/**
* Emitter gives classes which extend it
* the ability to listen for and emit events.
* Inspiration and reference from Jerome Etienne's [MicroEvent](https://github.com/jeromeetienne/microevent.js).
* MIT (c) 2011 Jerome Etienne.
* @category Core
*/
export class Emitter extends Tone {
constructor() {
super(...arguments);
this.name = "Emitter";
}
/**
* Bind a callback to a specific event.
* @param event The name of the event to listen for.
* @param callback The callback to invoke when the event is emitted
*/
on(event, callback) {
// split the event
const events = event.split(/\W+/);
events.forEach((eventName) => {
if (isUndef(this._events)) {
this._events = {};
}
if (!this._events.hasOwnProperty(eventName)) {
this._events[eventName] = [];
}
this._events[eventName].push(callback);
});
return this;
}
/**
* Bind a callback which is only invoked once
* @param event The name of the event to listen for.
* @param callback The callback to invoke when the event is emitted
*/
once(event, callback) {
const boundCallback = (...args) => {
// invoke the callback
callback(...args);
// remove the event
this.off(event, boundCallback);
};
this.on(event, boundCallback);
return this;
}
/**
* Remove the event listener.
* @param event The event to stop listening to.
* @param callback The callback which was bound to the event with Emitter.on.
* If no callback is given, all callbacks events are removed.
*/
off(event, callback) {
const events = event.split(/\W+/);
events.forEach((eventName) => {
if (isUndef(this._events)) {
this._events = {};
}
if (this._events.hasOwnProperty(eventName)) {
if (isUndef(callback)) {
this._events[eventName] = [];
}
else {
const eventList = this._events[eventName];
for (let i = eventList.length - 1; i >= 0; i--) {
if (eventList[i] === callback) {
eventList.splice(i, 1);
}
}
}
}
});
return this;
}
/**
* Invoke all of the callbacks bound to the event
* with any arguments passed in.
* @param event The name of the event.
* @param args The arguments to pass to the functions listening.
*/
emit(event, ...args) {
if (this._events) {
if (this._events.hasOwnProperty(event)) {
const eventList = this._events[event].slice(0);
for (let i = 0, len = eventList.length; i < len; i++) {
eventList[i].apply(this, args);
}
}
}
return this;
}
/**
* Add Emitter functions (on/off/emit) to the object
*/
static mixin(constr) {
// instance._events = {};
["on", "once", "off", "emit"].forEach((name) => {
const property = Object.getOwnPropertyDescriptor(Emitter.prototype, name);
Object.defineProperty(constr.prototype, name, property);
});
}
/**
* Clean up
*/
dispose() {
super.dispose();
this._events = undefined;
return this;
}
}
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