setState for array code example

Example 1: how to add array data on state react

this.setState({ myArray: [...this.state.myArray, 'new value'] }) //simple value
this.setState({ myArray: [...this.state.myArray, ...[1,2,3] ] }) //another array

Example 2: how to update array in react state

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

Example 3: add object to array setstate

To push to the beginning of the array do it this way

   this.setState( prevState => ({
     userFavorites: [{id: 3, title: 'C'}, ...prevState.userFavourites]
  }));

Example 4: react native update state array of objects

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