@theatrejs/theatrejs
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🎮 A JavaScript 2D Game Engine focused on creating pixel art games.
85 lines (66 loc) • 1.53 kB
JavaScript
/**
* Creates Event Buses.
* @template {string} [TypeGeneric=string] The generic type of the events.
*
* @example
*
* const eventbus = new EventBus();
*
* eventbus.trigger(EVENT);
*
* eventbus.listen(EVENT, handler);
*/
class EventBus {
/**
* @callback TypeListener An event listener.
* @param {TypeGeneric} $event The event to listen.
* @protected
*
* @memberof EventBus
*/
/**
* Stores the event listeners.
* @type {Object<string, Array<TypeListener>>}
* @private
*/
$listeners;
/**
* Creates a new event bus.
*/
constructor() {
this.$listeners = {};
}
/**
* Listens an event.
* @param {TypeGeneric} $event The event to listen.
* @param {TypeListener} $handler The listener to add.
* @returns {this}
* @public
*/
listen($event, $handler) {
if (Object.hasOwn(this.$listeners, $event) === false) {
this.$listeners[$event] = [];
}
this.$listeners[$event].push($handler);
return this;
}
/**
* Triggers an event.
* @param {TypeGeneric} $event The event to trigger.
* @returns {this}
* @public
*/
trigger($event) {
if (Object.hasOwn(this.$listeners, $event) === false) {
return this;
}
this.$listeners[$event].forEach(($handler) => {
$handler($event);
});
return this;
}
}
export {
EventBus
};
export default EventBus;