How to #import external SCSS properly with webpack and Vue.js? - sass

Question

As in Material Component Web's example, I want to be able to import SCSS from my node_modules like this:
#import '#material/elevation/mdc-elevation';
However, I'm getting this error message when trying to run the webpack build:
File to import not found or unreadable: #material/elevation/mdc-elevation.
#import './~/#material/elevation/mdc-elevation.scss'; doesn't work either.
I'm pretty sure the issue is somewhere in my webpack config, but I can't figure out where.
What did they do in Material Components Web's Vue.js example in order to make it work?
Here's my npm-debug.log in case you need it.
And here's the corresponding Git repository: sk22/spg-tinf-sem03/proj01
Thanks in advance!
Edit: I want to be able to import the scss files, not the compiled css.

Answer 1

Got it.
here's a part of my webpack 2 config's module.rules:
{
test: /\.(sass|scss)$/,
use: [
'style-loader',
'css-loader',
{
loader: 'sass-loader',
options: {
includePaths: [path.resolve(__dirname, 'node_modules')],
},
},
],
},
So what did I do wrong?
My options object was placed in the rule directly, not the loader.
The old webpack config rule looked like this:
{
test: /\.(sass|scss)$/,
use: ['style-loader', 'css-loader', 'sass-loader'],
options: { includePaths: [path.resolve(__dirname, './node_modules')] },
},
See the difference? Instead of the 'sass-loader' string, I extended it to an object, containing the loader name and the options object, because the options only apply to the sass-loader.
(You could also drop the path.resolve and only write 'node_modules', but it might be safer to leave it.)
Check out this documentation page for further information. https://webpack.js.org/configuration/module/#rule-use
Without that loader, you must prefix each import with a ~, which webpack converts to the node_modules folder, at least with my previous configuration.
But this will break 3rd party SCSS frameworks like Material Components Web, because they use #import statements without a leading ~ themselves, for example here.
Inside .vue files
This will not work in .vue files, as vue-loader just uses sass-loader without any options by default.
So if you want that to work, you probably need to make use of vue-loader's own options, as described in its documentation.
(I'm unable to get it to work for some reason I don't know...)

Answer 2

EDIT: Webpack has a section on sass-loader now: https://webpack.js.org/loaders/sass-loader/ also mentioning includepaths.
I had the same issue with #material and Vue. I managed to resolve the problem without adjusting the use property directly.
Solution
Step 1: First create a default Vue 2.1 project using the CLI.
Your file structure will have a ./build directory.
Step 2: Open the file 'utils' you will see a cssLoaders() function which returns an object/map for the languages vue-loader supports.
You will see both sass and scss in that map.
Step 3: Change the values of sass and scss to:
sass: generateLoaders('sass', {
indentedSyntax: true,
includePaths: [path.resolve(__dirname, '../node_modules')]
}),
scss: generateLoaders('sass', {
includePaths: [path.resolve(__dirname, '../node_modules')]
}),
Step 4: Go to the .vue file you're using and change the lang attribute in your <style> element to either sass or scss.
Step 5: After you've done that go to the terminal/console and install sass-loader with:
npm install sass-loader node-sass webpack --save-dev
Step 6: Then run npm run dev and it should work.
Why does this work?
Libraries
I dug around a bit and it turns out sass-loader uses node-sass which has some options such asincludePaths one mentioned by #22samuelk. IncludePaths tells node-sass or rather the underlying library LibSass to include sass files from that directory/path.
Vue
Sass-loader options
By default Vue expects your assets to be in your projects src/assets folder (correct me if I'm wrong). You can however use ~ to indicat you want to start at your projects root which would look like `~/node_modules/#material/smth/mdc-smth.scss.
Now if you want your sass-loader to use something other than those options you need to explicitly tell them.
Hence path.resolve(__dirname, '../node_modules' since the utils file is in ./build and you need to use an absolute path for sass-loader to understand where to look.
Vue-loader config
This is not really specific to the question but the vue-loader config defined in vue-loader.conf.js works as follows:
It uses the map returned by cssLoaders() to build the loaders expected by webpack.
The returned map ({key:value}) is then used by providing key as a file extension used in test: for a loader object. The value is used as the loader object.
Which would like like this:
{
test: /\.(key)$/,
use: [
{
loader: '//ld//-loader',
options: {
/*Options passed to generateLoaders('//ld//', options)*/
},
},
],
}
Where key is the file extention. In this case that would be either sass or scss. And //ld//is the loader you which to use. Which is shown in Step 3 as 'sass'.
Hopefully this clears up some stuff. Took me a while because I just started using Vue.