ReferenceError: fetch is not defined in NodeJs

# ReferenceError: fetch is not defined in NodeJs

The "ReferenceError: fetch is not defined" occurs when the fetch() method is used in an environment where it's not supported - most commonly Node.js.

To solve the error, install and import the node-fetch package, which provides a fetch() compatible API in the Node.js runtime.

Note that the global fetch variable is available in Node.js starting at version 18.

You can check your version of Node.js with the node -v command.

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node -v

If you use a Node.js version older than 18, you can either download and install the LTS version from nodejs.org or install and use the node-fetch package.

If your project doesn't have a package.json file, create one in your project's root directory:

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# 👇️ only run this if you don't have package.json file yet
npm init -y

Now install the node-fetch library by running the following command.

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# 👇️ with NPM
npm install node-fetch

# 👇️ only if you use TypeScript
npm install @types/node-fetch --save-dev

# --------------------------------------------

# 👇️ with YARN
yarn add node-fetch

# 👇️ only if you use TypeScript
yarn add @types/node-fetch --dev

Now you can import and use the module just like you would use the fetch() method in the browser.

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import fetch from 'node-fetch';

async function getUser() {
  try {
    const response = await fetch('https://randomuser.me/api/');

    if (!response.ok) {
      throw new Error(`Error! status: ${response.status}`);
    }

    const result = await response.json();
    return result;
  } catch (err) {
    console.log(err);
  }
}

console.log(await getUser());

At the time of writing, to use ES6 module imports and exports in a NodeJs project, you have to set the type property to module in your package.json file:

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{
  "type": "module",
  // ... 👇️ rest
}

If I run my NodeJs script, I get the result from calling the API.

# ReferenceError fetch is not defined in NodeJs (older versions)

Only do this if you use an older NodeJs version and want to use the require syntax instead of import/export.

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npm install node-fetch@2

We installed version 2 of the node-fetch package.

Make sure you don't have the type property set to module in your package.json file.

Now you can import the fetch package using the older require function.

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// 👇️ Using older require syntax
const fetch = require('node-fetch');

async function getUser() {
  try {
    const response = await fetch('https://randomuser.me/api/');

    if (!response.ok) {
      throw new Error(`Error! status: ${response.status}`);
    }

    const result = await response.json();
    return result;
  } catch (err) {
    console.log(err);
  }
}

We had to install version 2 of the node-fetch package to be able to use the require syntax in our NodeJs application.

It's best to stay consistent with imports between your client and server-side code. However, this approach gets the job done if you have to support an older version of NodeJs.