referenceerror fetch is not defined

Referenceerror: fetch is not defined

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As a JavaScript developer, you might come across the “ReferenceError: fetch is not defined” error message.

This error commonly arises when attempting to utilize the fetch API for making HTTP requests, but the fetch function is either unrecognized or unavailable in your current environment.

In this article, we will examine the potential causes of this error and offer practical solutions to resolve it.

What is Referenceerror: fetch is not defined?

The error “ReferenceError: fetch is not defined” arises when attempting to utilize the fetch() function in a setting where it is not compatible, typically observed in Node.js.

Typical Reasons for the ReferenceError

The “ReferenceError: fetch is not defined” error can be caused by several common factors:

Absence of Polyfill.

The fetch API is not universally supported in all web browsers, particularly older versions.

If you intend to use fetch in an environment lacking support, you must incorporate a polyfill to emulate the missing functionality.

Incompatibility with Browsers.

Certain older web browsers do not inherently support the fetch API and may necessitate additional configuration or polyfills to enable its functionality.

Solutions – Referenceerror: fetch is not defined

Now that we already know what are the typical causes and understand the error, now it’s time to fix it.

Install and import the node-fetch package

To address the issue, you can resolve it by installing and importing the node-fetch package.

This package offers an API that is compatible with the fetch() function in the Node.js runtime.

Keep in mind that the global fetch variable can be accessed in Node.js from version 18 onwards.

You can verify the version of your Node.js installation by using the command “node -v”.

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.

However, if you’re stuck with a Node.js version older than 18, solve the error by using the node-fetch package.

Additionally, if your project lacks a package.json file, you should generate one in the main directory of your project.

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

Now, to install the node-fetch library, by executing the given command.

# 📌 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

At this point, you can import and employ the module in the same way as you would utilize the fetch() function within a web browser.

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());

As of the current writing, in order to utilize ES6 module imports and exports within a Node.js project, it is necessary to set the type property to “module” in your package.json file.

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

Alternative solution when using NodeJs (older versions)

In this case perform this step if you are utilizing an older version of Node.js and prefer to use the require syntax instead of import/export.

npm install node-fetch@2

Here, we installed version 2 of the node-fetch package.

Remember to 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.

// 📌 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);
  }
}

In order to support the use of the require syntax in our Node.js application, we installed version 2 of the node-fetch package.

Generally, it is recommended to maintain consistency in imports between client and server-side code.

However, this approach is suitable if you need to accommodate an older version of Node.js.

Anyway besides this error, we also have fixed errors that you can check which might help you when you encounter them.

Conclusion

In conclusion, the “ReferenceError: fetch is not defined” error can be frustrating, but thankfully, there are several solutions available to address it.

Remember to choose the solution that best fits your project requirements and the target browsers you need to support.

I think that’s all for this error. We hope this article has helped fix the issues.

Until next time! 😊

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