how to update state in class component react code example

Example 1: state with react functions

class Example extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  render() {
    return (
      

        
You clicked {this.state.count} times
         this.setState({ count: this.state.count + 1 })}>
          Click me
        
      
    );
  }
}

Example 2: update state in react

You have to use setState() for updating state in React
{
  hasBeenClicked: false,
  currentTheme: 'blue',
}

setState({
	hasBeenClicked: true
});

Example 3: react lifecycle hooks

class Content extends React.Component {
  // ...
  componentWillMount() {
    this.setState({ activities: data });
  }
  // ...
}

Example 4: reactjs update state example

{
  hasBeenClicked: false,
  currentTheme: 'blue',
}