webpack/hot/dev-server and webpack working in a node angular app

webpack.config.js

module.exports = {
  entry: {
    app: ['webpack/hot/dev-server', './app/app'], // => webpack-dev-server will work but webpack build won't
    app: ['./app/app', 'webpack/hot/dev-server'], // => both webpack-dev-server AND webpack build will work
    vendor: ['./app/vendor'],
    components: ['./app/components/home']
  }
};

Line 3 keeps returning an error that the angular.module cannot be found. Likely because of this error happening before app/app.js is loaded:

Uncaught Error: [HMR] Hot Module Replacement is disabled.

In line 4 the Hot Module Replacement error still happens, but it's after app/app.js has loaded and doesn't matter (at least on localhost).