JAVASCRIPT

route to change a part of component

<Route
  exact
  path="/"
  render={props => (
    <Page {...props} component={Index} title="Index Page" />
  )}
/>

<Route
  path="/about"
  render={props => (
    <Page {...props} component={About} title="About Page" />
  )}
/>


//Page Component
import React from "react"

/* 
 * Component which serves the purpose of a "root route component". 
 */
class Page extends React.Component {
  /**
   * Here, we define a react lifecycle method that gets executed each time 
   * our component is mounted to the DOM, which is exactly what we want in this case
   */
  componentDidMount() {
    document.title = this.props.title
  }

  /**
   * Here, we use a component prop to render 
   * a component, as specified in route configuration
   */
  render() {
    const PageComponent = this.props.component

    return (
      <PageComponent />
    )
  }
}

export default Page