"use strict";

function once(event_emitter, event_name, abort_signal = null) {
	return new Promise((resolve, reject) => {
		let options = {
			once: true
		};
		if(abort_signal !== null) options.signal = abort_signal;
		
		let resolve_handler = function() {
			event_emitter.removeEventListener("error", reject);
			abort_signal.removeEventListener("abort", resolve_handler);
			resolve(...arguments);
		};
		
		abort_signal.addEventListener("abort", resolve_handler);
		event_emitter.addEventListener("error", reject, options);
		event_emitter.addEventListener(event_name, resolve_handler, options);
	});
}

export { once };