57 lines
1.4 KiB
JavaScript
57 lines
1.4 KiB
JavaScript
class Emitter {
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#listeners;
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constructor() {
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this.#listeners = new Map();
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}
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/**
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* Registers a callback function for the specified event.
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*
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* @param {string} event - The name of the event.
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* @param {Function} callback - The callback function to be executed when the event is triggered.
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*/
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on(event, callback) {
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if (!this.#listeners.has(event)) {
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this.#listeners.set(event, new Set());
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}
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this.#listeners.get(event).push(callback);
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}
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/**
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* Removes an event listener callback for the specified event.
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* If no callback is provided, removes all callbacks for the event.
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*
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* @param {string} event - The name of the event.
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* @param {Function} [callback] - The callback function to be removed.
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*/
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off(event, callback = undefined) {
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if (typeof event != 'string') return;
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if (!this.#listeners.has(event)) return false;
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if (!callback || this.#listeners.get(event).size === 0) {
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return this.#listeners.delete(event);
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}
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this.#listeners.get(event).delete(callback);
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}
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/**
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* Emits an event and invokes all registered listeners for that event.
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*
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* @param {string} event - The name of the event to emit.
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* @param {...any} args - The arguments to pass to the event listeners.
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*/
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emit(event, ...args) {
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if (!this.#listeners.has(event)) {
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return;
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}
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for (const callback of [...this.#listeners.get(event)]) {
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callback(this, ...args);
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}
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}
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}
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export default Emitter;
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