react-old-context.js

class App extends Component {
  static childContextTypes = {
    counter: PropTypes.object
  }

  constructor(props) {
    super(props);
    this.state = {
      count: 0,
      increment: this.increment
    };
  }

  increment = () => this.setState({count: this.state.count + 1});

  getChildContext() {
    return {
      counter: this.state
    }
  }

  render() {
    return (
      <div className="App">
        <header className="App-header">
          Counter
        </header>
        {this.props.children}
      </div>);
  }
}

class Layout extends Component {
  render() {
    return (
      <div>
          <Title />
          <Increment/>
      </div>
    );
  }
}

class Increment extends React.Component {
  static contextTypes = {
    counter: PropTypes.object,
  }

  render() {
    return <button onClick={this.context.counter.increment}> Inctement me</button>
  }
}


class Title extends React.Component {
  static contextTypes = {
    counter: PropTypes.object,
  }

  render = () => <h1>{this.context.counter.count}</h1>
}


export default function () {
  return (
    <App>
      <Layout/>
    </App>
  );
}