CounterButton.js

import React, {Component, PureComponent} from "react";

class CounterButton extends PureComponent{

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

    // shouldComponentUpdate(nextProps, nextState) {
    //     if(this.state.count!==nextState.count){
    //       return true
    //     }
    //     return  false
    //
    // }

    updateCount =()=>{
        this.setState(state=>{
            return {count:this.state.count+1}})

    }

    render() {
        console.log("CounterButton")

        return(
            <div>
                <button color={this.props.color} onClick={this.updateCount}>Count :{this.state.count} </button>

            </div>
        )
    }
}

export default CounterButton