Stateless Component

Caveats

  1. better use functions as argument for setState function

// Correct
this.setState((prevState, props) => ({
  counter: prevState.counter + props.increment
}));

  1. Reduce render times by doing magic in shouldComponentUpdate `. How React decide to render the component is according to 1. `shouldComponentUpdate function and 2. virtual DOM comparision, refer [here]() Try use [PureComponent](https://facebook.github.io/react/docs/react-api.html#react.purecomponent) and immutable props(especially for complex store) to avoid useless rendering.