Finally polyfill para versiones de node antiguas #node #finally #polyfill

node-finally-polyfill.md

Promise.prototype.finally = function (cb) {
    const res = () => this;
    return this.then(value =>
            Promise.resolve(cb({state: "fulfilled", value})).then(res)
        , reason =>
            Promise.resolve(cb({state: "rejected", reason})).then(res)
    );
};