parallelize/promise-listener.js

"use strict";

const consumable = require("@joepie91/consumable");

module.exports = function createPromiseListener() {
	let listeners = consumable([]);

	function consumeListeners() {
		/* To ensure that a resolve/reject is atomic, and can never apply to the same listener queue twice. */
		return listeners.replace([]);
	}

	return {
		listen: function () {
			return new Promise((resolve, reject) => {
				listeners.peek().push({ resolve, reject });
			});
		},
		resolve: function (value) {
			consumeListeners().forEach((listener) => {
				listener.resolve(value);
			});
		},
		reject: function (value) {
			consumeListeners().forEach((listener) => {
				listener.reject(value);
			});
		},
	}
};