changing style of a div in reactjs picking a random color from a array

changing style of a div in reactjs picking a random color from a array
running code->https://stackblitz.com/edit/react-62igcp
code:->

import React, { Component } from 'react';

import { render } from 'react-dom';

import './style.css';

class App extends Component {

constructor() {

super();

this.state = {

color: 'blue'

};

}

getRandomColor()

{

var colorArray=[

"blue","red","grreen","pink","yellow","orange","DodgerBlue","Tomato"

];

var index=Math.round(Math.random()*(colorArray.length-1));

const newColor= colorArray[index];

this.setState({color:newColor});

}

render() {

return (

<div style={{background: this.state.color}}>

<div ></div>

<div>click on button to change background color</div>

<span><button onClick={()=>{

this.getRandomColor();

}}>Click on button to change color</button></span>

</div>

);

}

}

render(<App />, document.getElementById('root'));