Example of a basic IFrame component and respective configuration with react-router

config.jsx

<BrowserRouter>
  <Route component={IFrame} path={['/messages', '/messages/thread/new', '/messages/thread/:id']} />
</BrowserRouter>

IFrame.jsx

class IFrame extends PureComponent {
  constructor(props) {
    super(props);
  
    this.iframeElement = React.createRef();
  
    this.handleLoad = this.handleLoad.bind(this);
  }
  
  handleLoad() {
    // ...
  }

  render() {
    const { location } = this.props;
    
    const url = '/_content' + location.pathname + location.search + location.hash;
    
    return <iframe ref={this.iframeElement} src={url} onLoad={this.handleLoad} />;
  }
}