Function to

bootstrap-js/modules/ts_helpers.js:241–251

(promise, improved)

 * @return [error, result]
 */
export function to(promise, improved){
    return promise
        .then((data) => [null, data])
        .catch((err) => {
            if (improved) {
                Object.assign(err, improved);
            }

            return [err]; // which is same as [err, undefined];
        });
}

/**
 * returns