script.jsx

class MyComponent extends React.Component {
    // when the component is added to the DOM...
    componentDidMount() {
        window.addEventListener(‘resize’, this.onResizeHandler);
    }

    // when the component is removed from the DOM...
    componentWillUnmount() {
        window.removeEventListener(‘resize’, this.onResizeHandler);
    }

    onResizeHandler() {
        console.log(‘The window has been resized!’);
    }
}