In this case I've and array by using useState

const [acts, setActs] = useState([])

now the point is that I want to push item at 4th index in array, and it should look like this

['', '', '', '' ,'should be here', '', '']

So, the method I'm trying to do this is here

let actsArray = []
const [acts, setActs] = useState(actsArray)

const addItem = (index) => {
   actsArray.splice(index, 0, 'Should be here')
   setActs(actsArray)
}