react-09.jsx

class MyComponent extends Component {
  
  constructor(props) {
    super(props);
    this.state = { value: { foo: 'bar' } };
  }

  onClick() {
    var value = this.state.value;
    value.foo += 'bar'; // value is reference to the current state, so current state and next state will be the same in next SCU call...
    this.setState({ value: value });
  }

  render() {
    return (
      <div>
        <InnerComponent value={this.state.value} />
        <a onClick={this.onClick}>Click me</a>
      </div>
    );
  }
  
}

class InnerComponent extends Component {
  
  shouldComponentUpdate(next, previous) {
    return next !== previous;
  }
  
  //other stuff
}