React-controlledForm

class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: '',
      submit: ''
    };
    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }
  handleChange(event) {
    this.setState({
    // SETS THE INPUT STATE TO THE TYPED INPUT
      input: event.target.value
    });
  }
  handleSubmit(event) {
    // THE METHOD BELOW PREVENTS THE DEFAULT FORM SUBMIT BEHAVIOR WHICH WILL REFRESH THE WEB PAGE
    event.preventDefault();
    this.setState({
    // SETS THE SUBMIT PROPERTY TO THE INPUT STATE
      submit : this.state.input
      });
  }
  render() {
    return (
      <div>
        { /* THE EVENT HANDLER IS ADDED IN THE FORM ELEMENT AND NOT IN THE SUBMIT B */ }
        <form onSubmit={this.handleSubmit}>
          { /* SETS THE INITIAL INPUT VALUE TO THE CLASS STATE AND THEN CHANGES THIS VALUE AS INPUT IS ADDED */ }
          <input value = {this.state.input} onChange = {this.handleChange}/>
          <button type='submit'>Submit!</button>
        </form>
          <h1>{this.state.submit}</h1>
      </div>
    );
  }
};