Polyfill for util.promisify in node versions < v8

node v8.0.0 added support for a built-in util.promisify: nodejs/node#12442

This package provides the built-in util.promisify in node v8.0.0 and later, and a replacement in other environments.

Direct

const promisify = require('util.promisify');
// Use `promisify` just like the built-in method on `util`

Shim

require('util.promisify/shim')();
// `util.promisify` is now defined
const util = require('util');
// Use `util.promisify`

Note: this package requires a native ES5 environment, and for Promise to be globally available. It will throw upon requiring it if these are not present.