const Demo = React.memo((props)=>{
console.log('rendering Demo');
return
Testing
;});class Example extends React.Component{
constructor(props){
super(props);
this.state={a:0};
}
componentDidMount(){
setInterval(()=>{
this.setState((state,props)=>({a:state.a+1}));
},1000);
}
render(){
console.log('rendering Example'); //return (); // re-renders Demo repeatedly
return ();
}}ReactDOM.render(
,
document.querySelector('div'));