Check props on componentWillMount

Router.js

class Component extends React.Component {
  componentWillMount() {
    warning(
      !(this.props.component && this.props.render),
      "You should not use <Route component> and <Route render> in the same route; <Route render> will be ignored"
    );

    warning(
      !(
        this.props.component &&
        this.props.children &&
        !isEmptyChildren(this.props.children)
      ),
      "You should not use <Route component> and <Route children> in the same route; <Route children> will be ignored"
    );

    warning(
      !(
        this.props.render &&
        this.props.children &&
        !isEmptyChildren(this.props.children)
      ),
      "You should not use <Route render> and <Route children> in the same route; <Route children> will be ignored"
    );
  }
 }