70 lines
1.6 KiB
JavaScript
70 lines
1.6 KiB
JavaScript
class Emitter {
|
|
#listeners;
|
|
constructor() {
|
|
this.#listeners = {};
|
|
}
|
|
|
|
/**
|
|
* Registers a callback function for the specified event.
|
|
*
|
|
* @param {string} event - The name of the event.
|
|
* @param {Function} callback - The callback function to be executed when the event is triggered.
|
|
*/
|
|
on(event, callback) {
|
|
if (!this.#listeners[event]) {
|
|
this.#listeners[event] = [];
|
|
}
|
|
this.#listeners[event].push(callback);
|
|
}
|
|
|
|
/**
|
|
* Removes an event listener callback for the specified event.
|
|
* If no callback is provided, removes all callbacks for the event.
|
|
*
|
|
* @param {string} event - The name of the event.
|
|
* @param {Function} [callback] - The callback function to be removed.
|
|
*/
|
|
off(event, callback = undefined) {
|
|
if (typeof event != 'string') {
|
|
throw new TypeError('event must be a string');
|
|
return;
|
|
}
|
|
|
|
if (
|
|
!Array.isArray(this.#listeners[event]) ||
|
|
this.#listeners[event].length === 0
|
|
) {
|
|
throw new TypeError(
|
|
`listener for \`${event}\` is not an array or empty`
|
|
);
|
|
}
|
|
|
|
if (!callback) {
|
|
this.#listeners[event] = undefined;
|
|
return;
|
|
}
|
|
|
|
this.#listeners[event] = this.#listeners[event].filter(
|
|
(listener) => listener !== callback
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Emits an event and invokes all registered listeners for that event.
|
|
*
|
|
* @param {string} event - The name of the event to emit.
|
|
* @param {...any} args - The arguments to pass to the event listeners.
|
|
*/
|
|
emit(event, ...args) {
|
|
if (!this.#listeners[event]) {
|
|
return;
|
|
}
|
|
|
|
for (const callback of this.#listeners[event]) {
|
|
callback(this, ...args);
|
|
}
|
|
}
|
|
}
|
|
|
|
export default Emitter;
|