What is the difference between ComponentWillMount and ComponentDidMount in React JS?

Question

Need to understand about the difference between these two func in ReactJs. ComponentWillMount(){} VS ComponentDidMount(){}

Answer 1

componentWillMount() gets called before first render whereas componentDidMount() gets called after first render. Both of these components gets called only once

Please note that componentWillMount() is deprecated in latest React version v16

Answer 2

Most discussed topic still explaining my understanding. ComponentWillMount executes before render as name suggest ComponentAfterMount executes before render once component gets rendered on screen as name suggest.

look at console logs in example

class App extends React.Component {
  componentWillMount(){
     console.log("console loging before component will mount");
  }
  componentDidMount(){
     console.log("console loging after mounting component");
  }
  render(){
    console.log("rendering component")
    return(
     <div> component</div>
    )
  }
}
ReactDOM.render(<App />, document.getElementById('root'))

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>

<div id='root' />