How can I insert into React's state array with setState?

Question

I\'m looking to modify and array in react and insert elements on specific index. This is how my state looks like:

this.state = {arr: [\'\', \'\', \'\', \'\' ]}
<         


        

Answer 1

use spread operator https://codeburst.io/javascript-es6-the-spread-syntax-f5c35525f754

let newChild = "newChild"

this.setState({
    children: [
        ...this.state.children,
        newChild
    ]
})