a good example to fetch in javaScript or React

Example 1: using componentdidmount with fetch

Component with Data
class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      items: [],
      isLoaded: false,
    };
  }

  componentDidMount() {
    fetch('https://jsonplaceholder.typicode.com/posts')
      .then(res => res.json())
      .then(result => {
        this.setState({
          isLoaded: true,
          items: result
        });
      });
  }

  render() {
    const { items } = this.state;
    if (!isLoaded) {
      return <div>Loading ... </div>;
    } else {
      return (
        <ul>
          {items.map(item => (
            <li key={item.id}>
              <h3>{item.title}</h3>
              <p>{item.body}</p>
            </li>
          ))}
        </ul>
      );
    }
  }
}
Fetching Data - Ha

Example 2: using componentdidmount with fetch

import React, { Component } from 'react';
class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      data: null,
    };
  }
  componentDidMount() {
    fetch('https://api.mydomain.com')
      .then(response => response.json())
      .then(data => this.setState({ data }));
  }
  ...
}
export default App;