You could always promisify functions manually, or with this tiny package https://github.com/sindresorhus/pify but yeah it's nice to see that in the standard library.
util.promisify is now in Node core as shown in the Original Comment
By "oldie" function, do you mean functions that expect node-style callbacks?
e.g. function myCallback (err, result) {...}Correct. Most node core APIs are written this way and now core ships an utility function[0] to wrap those functions in a promise.
[0]: https://medium.com/@styfle/promises-in-node-js-8-x-core-d6a8...
It seems to me that Node should ship promisify-ed versions of all these functions (e.g. fs.readFileAsync). Over time they could replace the implementation with ones that use the OS Async APIs, though perhaps this step is unnecessary if you're already using an event loop underneath.
Until then you can use `mz` for a modernised API[0].
I mean, they've been debating about how to add a promisified API for years (see for example https://github.com/nodejs/node/pull/5020) but nothing has come of it. util.promisify is a welcome addition, but very late for a first step.
How incredibly uncanny. Just yesterday morning, I posted this question!
https://stackoverflow.com/questions/44260289/using-native-es...
The improvement on the 8.0.0 version is that such an "oldie" function can be Promisified. A great improvement.