Using Babelify to compile React results in React Router being undefined - browserify

Question

I'm using Gulp for my build system, with Browserify for compiling my JS. I had been using Reactify for JSX compilation, but thought I'd switch to Babelify to get some additional ES2015 features. No errors are thrown when compiling, but when I load my site in the browser I get the following error in my JS console:
Uncaught ReferenceError: Router is not defined
The line the error is referring to is:
var React = require('react');
in the main component file that is being loaded on the page.
The places where I am importing React Router are in my App.jsx file (which is the entrypoint for the application) and my routes.jsx file, where I define the routes:
App.jsx
var React = require('react'),
Router = require('react-router'),
routes = require('./routes.jsx');
Router.run(routes, function(Handler, state) {
var routeClasses = '';
for (var i = 1; i < state.routes.length; i++) {
routeClasses += state.routes[i].name + ' ';
}
React.render(<Handler classes={routeClasses.trim()} />, document.getElementById('root'));
});
routes.jsx
var React = require('react');
Router = require('react-router'),
Route = Router.Route,
DefaultRoute = Router.DefaultRoute,
App = require('./_layout/App.jsx'),
Editor = require('./editor/Editor.jsx');
module.exports = (
<Route name="app" path="/" handler={App}>
<DefaultRoute name="editor" handler={Editor} />
</Route>
);
Everything was working fine when using Reactify rather than Babelify. I'm using Gulp for my build process:
gulp.task('js', function() {
var browserify = require('browserify'),
watchify = require('watchify'),
minifyify = require('minifyify'),
babelify = require('babelify');
function bundle() {
b.bundle()
.on('error', function(error){
gutil.log(error);
})
.pipe(source('app.js'))
.pipe(gulp.dest(paths.client.js.build))
.pipe(gulpif(!isStartup, browserSync.stream()));
isStartup = false;
}
var map = isProd ? false : 'app.map.json';
var b = browserify({
cache: {},
packageCache: {},
entries: paths.client.js.dev,
debug: true,
plugin: [watchify]
})
.transform(babelify, {presets: ['es2015', 'react']})
.plugin('minifyify', {
map: map,
output: paths.client.js.build + 'app.map.json',
});
b.on('update', function(){
bundle();
});
b.on('log', gutil.log); // output build logs to terminal
bundle();
});
The working version, using Reactify, simply omits the .transform(babelify...) line and adds transform: reactify to the browserify() initialization code, i.e.
var b = browserify({
cache: {},
packageCache: {},
entries: paths.client.js.dev,
debug: true,
transform: reactify,
plugin: [watchify]
});

Answer 1

It's working with es2015 import X from Y syntax, e.g.
import React from 'react'