main.js
function promesify(err, res) {
    if (!err) return Promise.resolve(res);
    else return Promise.reject(err);
}
function promesify(err, res) {
    if (!err) return Promise.resolve(res);
    else return Promise.reject(err);
}
function promesify ( err , res ) { if ( ! err ) return Promise . resolve ( res ) ; else return Promise . reject ( err ) ; }
Private function to return a promise if no done is found
Private function to return a promise if no done is found