const { observable } = mobx;

const { observer } = mobxReact;

const { Component } = React;

​

@observer 

class App extends Component {

  @observable value = ''

  componentDidMount() {

    setTimeout(() => this.value = 'focus', 1000);

  }

  componentDidUpdate() {

    this.ref.focus();

  }

  render() {

    return (

      <input

        ref={ref => this.ref = ref}

        value={this.value}

        onChange={e => this.value = e.target.value}

      />

    );

  }

};

​

​

ReactDOM.render(

  <App />,

  document.getElementById('app')

);