Webpack, sass-loader (or css-loader) nested file imports inside node_modules. File not found

Question

I want to use primercss framework as sass. I am using webpack to build my application. I have downloaded the npm package and imported it using: @import "~primer-css/index.scss";. The problem is that the build fails with this error: File to import not found or unreadable: primer-core/index.scss , which is a subimport in the primer-css/index.scss file. I think that it is a problem related to the webpack sass-loader or css-loader, the full-stack trace is the following:

ERROR in ./node_modules/css-loader?{"modules":true,"minimize":true,"sourceMap":true,"importLoaders":2,"localIdentName":"[name]__[local]"}!./node_modules/postcss-loader/lib?{"config":{"path":"/Users/vicaba/Projects/medself/medself-client/development/webpack/postcss.config.js"},"sourceMap":true}!./node_modules/sass-loader/lib/loader.js?{"outputStyle":"expanded","sourceMap":true,"sourceMapContents":true}!./src/theme/theme.scss
Module build failed:
@import "primer-core/index.scss";
^
      File to import not found or unreadable: primer-core/index.scss.
Parent style sheet: /Users/vicaba/Projects/medself/medself-client/development/node_modules/primer-css/index.scss
      in /Users/vicaba/Projects/medself/medself-client/development/node_modules/primer-css/index.scss (line 14, column 1)
Error:
@import "primer-core/index.scss";
^
      File to import not found or unreadable: primer-core/index.scss.
Parent style sheet: /Users/vicaba/Projects/medself/medself-client/development/node_modules/primer-css/index.scss
      in /Users/vicaba/Projects/medself/medself-client/development/node_modules/primer-css/index.scss (line 14, column 1)
    at options.error (/Users/vicaba/Projects/medself/medself-client/development/node_modules/node-sass/lib/index.js:291:26)
 @ ./src/theme/theme.scss 4:14-200
 @ ./src/bootstrap.js
 @ multi ./src/bootstrap.js

ERROR in ./src/theme/theme.scss
Module build failed: ModuleBuildError: Module build failed:
@import "primer-core/index.scss";
^
      File to import not found or unreadable: primer-core/index.scss.
Parent style sheet: /Users/vicaba/Projects/medself/medself-client/development/node_modules/primer-css/index.scss
      in /Users/vicaba/Projects/medself/medself-client/development/node_modules/primer-css/index.scss (line 14, column 1)
    at runLoaders (/Users/vicaba/Projects/medself/medself-client/development/node_modules/webpack/lib/NormalModule.js:194:19)
    at /Users/vicaba/Projects/medself/medself-client/development/node_modules/loader-runner/lib/LoaderRunner.js:364:11
    at /Users/vicaba/Projects/medself/medself-client/development/node_modules/loader-runner/lib/LoaderRunner.js:230:18
    at context.callback (/Users/vicaba/Projects/medself/medself-client/development/node_modules/loader-runner/lib/LoaderRunner.js:111:13)
    at Object.asyncSassJobQueue.push [as callback] (/Users/vicaba/Projects/medself/medself-client/development/node_modules/sass-loader/lib/loader.js:55:13)
    at Object.<anonymous> (/Users/vicaba/Projects/medself/medself-client/development/node_modules/async/dist/async.js:2244:31)
    at Object.callback (/Users/vicaba/Projects/medself/medself-client/development/node_modules/async/dist/async.js:906:16)
    at options.error (/Users/vicaba/Projects/medself/medself-client/development/node_modules/node-sass/lib/index.js:294:32)

The loaders configuration is the following:

{
  test: /\.scss$/,
  use: ExtractTextPlugin.extract({
    fallback: 'style-loader',
    use: [
      {
        loader: 'css-loader',
        options: {
          modules: true,
          minimize: true,
          sourceMap: true,
          importLoaders: 2,
          localIdentName: '[name]__[local]'
        }
      },
      {
        loader: 'postcss-loader',
        options: {
          config: {
            path: path.resolve(__dirname, 'postcss.config.js')
          },
          sourceMap: true
        }
      },
      {
        loader: 'sass-loader',
        options: {
          outputStyle: 'expanded',
          sourceMap: true,
          sourceMapContents: true
        }
      }
    ]
  })
}

Can anyone help me? Or shed some light on the problem?

Answer 1

So I think I should say that this issue seems very much unresolved and it doesn't even seem clear if it will be resolved as sass-loader is officially saying there is no problem, because this is how node-sass is supposed to work.

If people are interested in the reading the official issue thread, it's still open over here on github. There are a couple of quick hacks described in the thread, but none of them worked that well for me, although they all basically do the same thing which is including the node_modules folder in sass-imports.

The reason they do this is because as you have described when you have a simple file that looks like:

 @import "~primer-css/index.scss";

This does rely on sub-imports or external SASS files in the node_modules folder. To be specific, these:

/*!
 * Primer
 * http://primer.github.io
 *
 * Released under MIT license. Copyright (c) 2017 GitHub Inc.
 */

// Primer master file
//
// Imports all Primer files in their intended order for easy mass-inclusion.
// Should you need specific files, you can easily use separate `@import`s.

// Global requirements
@import "primer-core/index.scss";
@import "primer-product/index.scss";
@import "primer-marketing/index.scss";

Because none of these sub-imports have the ~ in front of them, they aren't resolved.

In fact, if you just try and compile primer-support/index.scss it will actually work out of the box because all it's imports only depend on it's own module and thus it resolves:

// variables
@import "./lib/variables/typography.scss";
@import "./lib/variables/colors.scss";
@import "./lib/variables/layout.scss";
@import "./lib/variables/misc.scss";

// mixins
@import "./lib/mixins/typography.scss";
@import "./lib/mixins/layout.scss";
@import "./lib/mixins/buttons.scss";
@import "./lib/mixins/misc.scss";

Nonetheless, after way longer than it should have taken there does seem to be a way around this, as commented in this post

   {
    test: /\.s?css$/,
    loaders: [
      'css',
      'sass?includePaths[]='+ path.resolve(__dirname, 'node_modules') +
        '&includePaths[]='+ path.resolve(__dirname, 'bower_components')
        // tells sass-loader to look in these dirs when resolving files
    ]
  }

Which I changed to:

        {
            test: /\.scss$/,
            use: ExtractTextPlugin.extract({
                fallback: "style-loader",
                use: "css-loader?importLoaders=1!postcss-loader!sass-loader?includePaths[]=" + resolve(__dirname, 'node_modules')
            })
        }

Because I only wanted it checking for SCSS and because I wanted to both my CSS and SCSS to be bundled and minified together.

However, this probably probably won't work for most people so I guess to fix your code sample it would look like:

     {
        loader: 'sass-loader',
        options: {
          config: {
            path: path.resolve(__dirname, 'node_modules')
          },
          outputStyle: 'expanded',
          sourceMap: true,
          sourceMapContents: true
        }
      }

But I found the config to be quite tricky, so ultimately I think the easiest way to include it is just by modifying the loader use to:

sass-loader?includePaths[]=" + resolve(__dirname, 'node_modules')