find in array and change state react code example

Example 1: how to update array in react state

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

Example 2: react native update state array of objects

let newMarkers = markers.map(el => (
      el.name==='name'? {...el, key: value}: el
))
this.setState({ markers });