Mocking fetch in Jest

ExampleComponent.js

import React, { Component } from 'react';

class ExampleComponent extends Component {
  componentDidMount() {
    const fetchedData = this.fetchDataFromServer();
    
    // ... do something with fetchedData e.g. set the data
  }
  
  async fetchDataFromServer() {
    try {
      const response = await fetch('https://url-of-your-server.com/example/json'); // 1
      return await response.json(); // 2
    } catch (error) {
      // ... gracefully handle error
    }
  }
  
  // ...
}