Posted on Arjun

Node Js – convert a callback-based function to a Promise-based one?

In this post you will learn how to convert a callback-based function to a promise-based one using util.promisify() function.As a part of Node Js version 8, promisify() function added to util module.

In simple worlds util.promisify() function converts a regular function into a promise. The final paramter of the function passed to promisify must be a callback and it should follow Node’s callback style. i.e. taking a (err, value) => ... callback as the last argument, and returns a version that returns promises.


In this above example, you can see that, we are getting response in callback style. Now lets convert it to Promise

Or, equivalently using async functions:

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I am Arjun from Hyderabad (India). I have been working as a software engineer from last 7+ years, and its my passion to learn new things and implement them as a practice. Aside from work, I likes gardening and spending time with pets. Protection Status