util

​​ promisify/callbackify

The promisify and callbackify APIs in Node.js provide a means of bridging between a Promise-based programming model and a callback-based model.

The promisify method allows taking a Node.js-style callback function and converting it into a Promise-returning async function:

Similarly to promisify, callbackify converts a Promise-returning async function into a Node.js-style callback function:

callbackify and promisify make it easy to handle all of the challenges that come with bridging between callbacks and promises.

Refer to the Node.js documentation for callbackify Open external link and Node.js documentation for promisify Open external link for more information.

​​ util.types

The util.types API provides a reliable and efficient way of checking that values are instances of various built-in types.

For more about util.types, refer to the Node.js documentation for util.types Open external link .

​​ util.MIMEType

util.MIMEType provides convenience methods that allow you to more easily work with and manipulate MIME types Open external link . For example:

For more about util.MIMEType, refer to the Node.js documentation for util.MIMEType Open external link .