``` // One const arr = [7,8,9]; class WatchStore extends Component { constructor(props) { super(props); } ...... } // Two class WatchStore extends Component { constructor(props) { super(props); this.state = { arr: [7,8,9], } } ...... } // Three class WatchStore extends Component { constructor(props) { super(props); } componentDidMount() { this.arr = [7,8,9]; } ...... } ``` which is the best way to use the three defined methods? The arr does not need to be rendered, just make a temporary cache comparison new data use! Thanks!