Nodejs Util Promisify Is Not A Function

Are you encountering an issue with Node.js and receiving the error "util.promisify is not a function"? Don't worry, you're not alone, and we're here to help you understand and fix this common problem.

When you encounter the error "util.promisify is not a function" in Node.js, it typically means that the 'util' module is not being imported correctly in your code. This error often occurs when developers try to use util.promisify without requiring the 'util' module first.

To resolve this issue, you need to make sure you are importing the 'util' module at the beginning of your file. To do this, add the following line of code to your JavaScript file:

Javascript

const util = require('util');

By requiring the 'util' module in your code, you can then use the promisify function provided by Node.js to convert callback-based APIs into Promise-based ones. The promisify function is a utility function that helps you work with functions that follow the error-first callback style.

Once you have imported the 'util' module, you can use the promisify function like this:

Javascript

const util = require('util');
const fs = require('fs');

const readFileAsync = util.promisify(fs.readFile);

readFileAsync('example.txt', 'utf8')
  .then(data =&gt; {
    console.log(data);
  })
  .catch(error =&gt; {
    console.error(error);
  });

In this example, we are using promisify to convert the fs.readFile function, which traditionally uses a callback, into a Promise-based function. This allows us to use async/await or Promise syntax for handling asynchronous operations more efficiently.

Remember that the 'util' module is a built-in Node.js module, so you don't need to install any additional packages to use it. Just make sure to require it properly as shown above in your code.

In summary, if you encounter the error "util.promisify is not a function" in Node.js, make sure you import the 'util' module at the beginning of your file using `const util = require('util');`. This simple step will enable you to leverage the promisify function and work with Promise-based asynchronous operations seamlessly.

By following these steps and understanding how to use the promisify function, you can quickly resolve this error and enhance your coding experience with Node.js. Happy coding!

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