update react code example

Example 1: update react version

//Is used to update the version only; such as 16.0.0 can be update to latest 16.13.0 but.. 
//but.. 15.0.0 can't be updated to 16.13.0 or to 16.0.0 with this
npm update react

//Use this to go from 15.0.0 to 16.13.0
npm install --save react@latest

Example 2: setstate react js

constructor(props) {
        super(props);
        this.state = {
            isActive: true,
        };
    }

    checkStatus = () => {
        this.setState({		// use this function
            'isActive' : !this.state.isActive,
        });
    }

Example 3: how to update react app

//open terminal and run thsi code 
cd newreact
//where newreact is the old react app you created
//open package.json in text editor and change the version to latest
//open the same terminal gain and run this
npm install

Example 4: react lifecycle hooks

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