How to import and export components using React + ES6 + webpack?

Question

I'm playing around with React and ES6 using babel and webpack. I want to build several components in different files, import in a single file and bundle them up with webpack

Let's say I have a few components like this:

my-navbar.jsx

import React from 'react';
import Navbar from 'react-bootstrap/lib/Navbar';

export class MyNavbar extends React.Component {
    render(){
      return (
        <Navbar className="navbar-dark" fluid>
        ...
        </Navbar>
      );
    }
}

main-page.jsx

import React from 'react';
import ReactDOM from 'react-dom';

import MyNavbar from './comp/my-navbar.jsx';

export class MyPage extends React.Component{
  render(){
    return(
        <MyNavbar />
        ...
    );
  }
}

ReactDOM.render(
  <MyPage />,
  document.getElementById('container')
);

Using webpack and following their tutorial, I have main.js:

import MyPage from './main-page.jsx';

After building the project and running it, I get the following error in my browser console:

Error: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. Check the render method of `MyPage`.

What am I doing wrong? How can I properly import and export my components?

Answer 1

Try defaulting the exports in your components:

import React from 'react';
import Navbar from 'react-bootstrap/lib/Navbar';

export default class MyNavbar extends React.Component {
    render(){
      return (
        <Navbar className="navbar-dark" fluid>
        ...
        </Navbar>
      );
    }
}

by using default you express that's going to be member in that module which would be imported if no specific member name is provided. You could also express you want to import the specific member called MyNavbar by doing so: import {MyNavbar} from './comp/my-navbar.jsx'; in this case, no default is needed