How to import CSS from node_modules in webpack angular2 app

Question

Let\'s say that we start with the following starter pack: https://github.com/angularclass/angular2-webpack-starter

After npm install and npm run start

Answer 1

You won't be able to import any css to your vendors file using that stack, without making some changes.

Why? Well because this line:

import 'bootstrap/dist/css/bootstrap.css';

It's only importing your css as string, when in reality what you want is your vendor css in a style tag. If you check config/webpack.commons.js you will find this rule:

 {
   test: /\.css$/,
   loaders: ['to-string-loader', 'css-loader']
 },

This rule allows your components to import the css files, basically this:

@Component({
  selector: 'app',
  encapsulation: ViewEncapsulation.None,
  styleUrls: [
    './app.component.css' // this why you import css as string
  ],

In the AppComponent there's no encapsulation, because of this line encapsulation: ViewEncapsulation.None, which means any css rules will be applied globally to your app. So you can import the bootstrap styles in your app component:

@Component({
  selector: 'app',
  encapsulation: ViewEncapsulation.None,
  styleUrls: [
    './app.component.css',
    '../../node_modules/bootstrap/dist/css/bootstrap.css'
  ],

But if you insist in importing to your vendor.ts then you will need to install a new loader, npm i style-loader --save-dev this will allow webpack to inject css to your page. Then you need to create a specific rule, on your webpack.common.js and change the existing one:

 { //this rule will only be used for any vendors
   test: /\.css$/,
   loaders: ['style-loader', 'css-loader'],
   include: [/node_modules/]
 },
 {
   test: /\.css$/,
   loaders: ['to-string-loader', 'css-loader'],
   exclude: [/node_modules/] //add this line so we ignore css coming from node_modules
 },

The firs rule will be only applied when you try to import css, from any package inside node_modules the second rule will be applied to any css that you import from outside the node_modules