@mightyplow/jslib/function/promisify.js

js helpers library

/**
 * @memberOf function
 * @param fn
 * @param context
 */
var promisify = function promisify(fn) {
    var context = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;
    return function () {
        for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
            args[_key] = arguments[_key];
        }

        return new Promise(function (resolve, reject) {
            // create a callback to handle error and data
            var callback = function callback(err, data) {
                return err ? reject(err) : resolve(data);
            };

            // call the original function with our callback flavoured arguments
            fn.call.apply(fn, [context].concat(args, [callback]));
        });
    };
};

export default promisify;