React JS-Render 호출 시기

why-did-you-render by Welldone Software monkey patches React to notify you about potentially avoidable re-renders

import React from "react";

class Counter extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      value: 0,
      unusedString: "Hey there!",
    };
  }

  shouldComponentUpdate(nextProps, nextState) {
    // If the method returns true, component is rerendered
    // If it return true, it is not rerenderd
    return this.state.value != nextState.value;
  }

  render() {
    return <div>{this.state.value}</div>;
  }
}

export default Counter;