Error XMLHttpRequest GET not working in React js

Question

I have a Profile class, like this :

 class Profile extends React.Component {
    state = {
        email: '',
        userName: '',
        userID: ''
    };

    getData() {
        var request = new XMLHttpRequest();

        request.onreadystatechange = function() {
            if (this.readyState == 4 && this.status == 200) {
                console.log(this.responseText);
            }
        };
        request.open('GET', 'http://localhost:8080/user/1');
        request.send();
        console.log(request.responseText);
    }

    render() {
        return ( <
            div >
            this.getData(); <
            /div>

        );
    }
}

The problem is it is not putting anything in the console.

Although http://localhost:8080/user/1 in browser returning me this :

{"userID":1,"passwordHash":"5994471abb01112afcc18159f6cc74b4f511b99806da59b3caf5a9c173cacfc5","email":"admin@admin.com"}

How to resolve this?

Answer 1

Hello @kartik,

You should populate data with AJAX calls in the componentDidMount lifecycle method. This is so you can use setState to update your component when the data is retrieved.

Example from react documentation

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      email: '',
      userName: '',
      userID: '',
      error: null,
      isLoaded: false
    };
  }

  componentDidMount() {

 fetch("http://localhost:8080/user/1")
      .then(res => res.json())
      .then(
        (result) => {
          this.setState({
            email: result.email,
            userName: result.userName,
            userID: result.userID
          });
        },
        // Note: it's important to handle errors here
        // instead of a catch() block so that we don't swallow
        // exceptions from actual bugs in components.
        (error) => {
          this.setState({
            isLoaded: true,
            error
          });
        }
      )
  }

  render() {
    const { error, isLoaded, email, userName, userID  } = this.state;
    return (
        <ul>
          {email}
          {userName}
          {userID}
        </ul>
    );
  }
}

Hope this work!

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Thank You!!