changing array in state react 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: react native update state array of objects

let markers = [ ...this.state.markers ];
markers[index] = {...markers[index], key: value};
this.setState({ markers });