where to update state array in react js code example

Example 1: how to update react state array

const [myArray, setMyArray] = useState([1,2,3])

// to update
setMyArray([...myArray, 4]); // --> myArray = [1,2,3,4]

Example 2: how to update array in react state

this.setState(prevState => ({
  arrayvar: [...prevState.arrayvar, newelement]
}))