What is the simplest way to mock a fetch call that is only meant to run in the browser with jest?-CodePudding

If I'm testing a function that makes a fetch call, and all the fetch calls I have in the project are only meant to run in the browser. Do I still need to have some package installed on node and import it to be able to mock that fetch call?

A simple scenario like this throws ReferenceError: fetch is not defined in the Jest test:

// fetcKey.js

export async function fetchKey() {
    try {

        const key = await fetch('http://localhost:3000/key');
        return (await key.text());
    }
    catch(error){
        throw error;
    }
}

//fetchKey.test.js

import fetchKey from './fetchKey'

test('Checks fetchKey return', () => {

    expect(fetchKey()).not.toThrow();

})

CodePudding user response：

You should be able to use node-fetch:

import fetch from 'node-fetch';

(Note it's an ECMAScript Module and cannot be imported with require, as mentioned in their documentation).