add item to array setstate hooks code example

Example 1: add items to a react array in hooks

const addMessage = (newMessage) => setMessages(state => [...state, newMessage])

Example 2: 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]
  }));