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

Clone the current state using slice(). By doing this, the original state remains unaffected till setState(). After cloning, do your operations over the cloned array and set it in the state. The previous answer will mutate the state. Read about this here

let a = this.state.arr.slice(); //creates the clone of the state
a[index] = "random element";
this.setState({arr: a});