Function when

when.js:82–89

* Get a trusted promise for x, or by transforming x with onFulfilled * * @param {*} x * @param {function?} onFulfilled callback to be called when x is * successfully fulfilled. If promiseOrValue is an immediate value, callback * will be invoked immediately. * @param {function?} onRe

(x, onFulfilled, onRejected, onProgress)

	 *   callback and/or errback is not supplied.
	 */
	function when(x, onFulfilled, onRejected, onProgress) {
		var p = Promise.resolve(x);
		if (arguments.length < 2) {
			return p;
		}

		return p.then(onFulfilled, onRejected, onProgress);
	}

	/**
	 * Creates a new promise whose fate is determined by resolver.