Function bindCallback

node.js:230–248

* Attaches a node-style callback to a promise, ensuring the callback is * called for either fulfillment or rejection. Returns a promise with the same * state as the passed-in promise. * * @example * var deferred = when.defer(); * * function callback(err, value) { * // Handle err or

(promise, callback)

	 * @returns {Promise} A promise with the same state as the passed-in promise.
	 */
	function bindCallback(promise, callback) {
		promise = when(promise);

		if (callback) {
			promise.then(success, wrapped);
		}

		return promise;

		function success(value) {
			wrapped(null, value);
		}

		function wrapped(err, value) {
			setTimer(function () {
				callback(err, value);
			}, 0);
		}
	}

	/**
	 * Takes a node-style callback and returns new function that accepts a