To create pre-loading of a component in ReactJS using reactJS lifecycle

App.js

import React from "react"
import LoadedDiv from './Loaded.js'
import PreLoadDiv from './preload-content.js'
export default class App extends React.Component{
  constructor(props){
    super(props);
    this.state ={ loading : false};

  }
  componentWillMount(){
    this.setState({  // re-renders the component everytime setState is called
      loading:true
    })

  }
  componentDidMount(){
    this.setState({ // re-renders the component everytime setState is called
      loading:false
    })

  }
  preLoadingTemplate(){
    return <div><PreLoadDiv /></div>;
  }
  postLoadingTemplate(){
    return <div><LoadedDIv /></div>;
  }
  render(){
    if(this.state.loading){
      return this.preLoadingTemplate();
    }
    return this.postLoadingTemplate();
  }
}

loaded.js

import React from 'react';
export default class LoadedDiv extends React.Component{
  render(){
    return (
      <div >
        <div className="container">
          <h1>Loaded Completly</h1>
        </div>
      </div>
    )
  }
}

preload-content.js

// Credit for the UI of this Div to https://github.com/sidhantpanda . The CodePen Link https://codepen.io/sidhantpanda/pen/VpXdKW

import React from 'react';
export default class PreLoadDiv extends React.Component{
  render(){
    return (
      <div  className="postLoadCard content-div">
          <div className="bodyWrap">
            <div className="loadingAnim"></div>
            <div className="loadingAnim"></div>
            <div className="loadingAnim"></div>
            <div className="loadingAnim"></div>
          </div>
          <div className="footerWrap"></div>
      </div>
    )
  }
}
/* styling .css content copy from here

.postLoadCard {
  -webkit-border-radius: 1px;
  -moz-border-radius: 1px;
  border-radius: 1px;
  -webkit-box-shadow: 0 1px 4px rgba(0, 0, 0, .04);
  -moz-box-shadow: 0 1px 4px rgba(0, 0, 0, .04);
  box-shadow: 0 1px 4px rgba(0, 0, 0, .04);
  border: 1px solid rgba(0, 0, 0, .09);
  border-color: transparent;
  background: rgba(255, 255, 255, .8);
  margin: 0 0 18px
}
.postLoadCard .bodyWrap {
  padding: 20px 16px 0
}
.postLoadCard .bodyWrap .loadingAnim {
  margin: 0 0 16px;
  max-width: 500px
}
.postLoadCard .bodyWrap .loadingAnim:first-child {
  padding: 16px;
  max-width: 90%;
}
.postLoadCard .bodyWrap .loadingAnim:last-child {
  padding: 8px;
  max-width: 250px
}
.postLoadCard .footerWrap {
  margin: 24px 0 0;
  padding: 24px 0
}
.postLoadCard .loadingAnim {
  padding: 6px;
  width: 100%;
  -webkit-border-radius: 2px;
  -moz-border-radius: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, rgba(207, 216, 220, .15), rgba(207, 216, 220, .35), rgba(207, 216, 220, .15));
  -webkit-animation: loadanimation 1.4s ease infinite;
  -moz-animation: loadanimation 1.4s ease infinite;
  animation: loadanimation 1.4s ease infinite;
  background-size: 600% 600%
}
.content-div{
  background-color:white;
  width:50%;
  margin:auto;
}
@-webkit-keyframes loadanimation {
  0% {
      background-position: 0 50%
  }
  50% {
      background-position: 100% 50%
  }
  100% {
      background-position: 0 50%
  }
}
@-moz-keyframes loadanimation {
  0% {
      background-position: 0 50%
  }
  50% {
      background-position: 100% 50%
  }
  100% {
      background-position: 0 50%
  }
}

@keyframes loadanimation {
  0% {
      background-position: 0 50%
  }
  50% {
      background-position: 100% 50%
  }
  100% {
      background-position: 0 50%
  }
}
*/