You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
70 lines
1.9 KiB
70 lines
1.9 KiB
if (!('EventEmitter' in window)) {
|
|
window.EventEmitter = class EventEmitter {
|
|
constructor () {
|
|
this._listeners = {}
|
|
}
|
|
|
|
/**
|
|
* Bind an event listener to an event
|
|
* @param {string} event - the event name
|
|
* @param {Function} listener - the event listener
|
|
*/
|
|
on (event, listener) {
|
|
if (!this._listeners[event]) this._listeners[event] = []
|
|
this._listeners[event].push({ listener })
|
|
}
|
|
|
|
/**
|
|
* Bind an event listener to be run only once the next time the event fires
|
|
* @param {string} event - the event name
|
|
* @param {Function} listener - the event listener
|
|
*/
|
|
once (event, listener) {
|
|
if (!this._listeners[event]) this._listeners[event] = []
|
|
this._listeners[event].push({ listener, once: true })
|
|
}
|
|
|
|
/**
|
|
* Remove an event listener
|
|
* @param {string} event - the event name
|
|
* @param {Function} listener - the event listener
|
|
*/
|
|
off (event, listener) {
|
|
let listeners = this._listeners[event]
|
|
if (listeners) {
|
|
for (let i in listeners) {
|
|
if (listeners[i].listener === listener) {
|
|
listeners.splice(i, 1)
|
|
break
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Emits an event
|
|
* @param {string} event - the event name
|
|
* @param {...any} args - arguments passed to all listeners
|
|
*/
|
|
emit (event, ...args) {
|
|
let listeners = this._listeners[event]
|
|
if (listeners) {
|
|
let remove = []
|
|
for (let listener of listeners) {
|
|
try {
|
|
listener.listener(...args)
|
|
if (listener.once) remove.push(listener)
|
|
} catch (err) {
|
|
console.error(err)
|
|
}
|
|
}
|
|
|
|
// this needs to be done in this roundabout way because for loops
|
|
// do not like arrays with changing lengths
|
|
for (let listener of remove) {
|
|
listeners.splice(listeners.indexOf(listener), 1)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|