react initial state

1class App extends React.Component {
2  constructor(props) {
3    // Required step: always call the parent class' constructor
4    super(props);
5
6    // Set the state directly. Use props if necessary.
7    this.state = {
8      loggedIn: false,
9      currentState: "not-panic",
10
11      // Note: think carefully before initializing
12      // state based on props!
13      someInitialValue: this.props.initialValue
14    }
15  }
16
17  render() {
18    // whatever you like
19  }
20}
21

1//initial state
2const [state, setState] = useState(0)
3//change state
4setState(1)
5//change state with prev state value
6setState((prevState) => {prevState + 2}) // 3