withTrackingClass.js

const withTracking = WrappedRoute => {
  return class PageViewWrapper extends Component {
    componentDidMount() {
      console.log(this.props);

      if (window.dataLayer) {
        window.dataLayer.push({
          event: "pageview or something"
        });
      }
    }

    render() {
      return <WrappedRoute {...this.props} />;
    }
  };
};