reactClass.js

import react from 'react';

class Person extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      name: ''
    };
    this.handleChange = this.handleChange.bind(this);
  }

  handleChange(e) {
    this.setState({
      name: e.target.value
    });
  }

  render() {
    return (
      <div>
        <input value={this.state.name} onChange={this.handleChange} />
      </div>
    );
  }
}