fetch data from backend in react code example

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: React get method

/* React get method.  */

componentWillMount(){
    fetch('/getcurrencylist',
    {
        /*
        headers: {
          'Content-Type': 'application/json',
          'Accept':'application/json'
        },
        */
        method: "get",
        dataType: 'json',
    })
    .then((res) => res.json())
    .then((data) => {
      var currencyList = [];
      for(var i=0; i< data.length; i++){
        var currency = data[i];
        currencyList.push(currency);
      }
      console.log(currencyList);
      this.setState({currencyList})
      console.log(this.state.currencyList);
    })
    .catch(err => console.log(err))
  }