npm install sass-loader

Starting with 1.0.0, the sass-loader requires node-sass as peerDependency. Thus you are able to specify the required version accurately.

Documentation: Using loaders

var css = require("!raw!sass!./file.scss");
// => returns compiled css code from file.scss, resolves imports
var css = require("!css!sass!./file.scss");
// => returns compiled css code from file.scss, resolves imports and url(...)s

Use in tandem with the style-loader to add the css rules to your document:

require("!style!css!sass!./file.scss");

It's recommended to adjust your webpack.config so style!css!sass! is applied automatically on all files ending on .scss:

module.exports = {
  module: {
    loaders: [
      {
        test: /\.scss$/,
        loader: "style!css!sass"
      }
    ]
  }
};

Then you only need to write: require("./file.scss").

You can pass any Sass specific configuration options through to the render function via query parameters.

module.exports = {
  module: {
    loaders: [
      {
        test: /\.scss$/,
        loader: "style!css!sass?outputStyle=expanded&" +
          "includePaths[]=" +
            (path.resolve(__dirname, "./bower_components")) + "&" +
          "includePaths[]=" +
            (path.resolve(__dirname, "./node_modules"))
      }
    ]
  }
};

See node-sass for all available options.

webpack provides an advanced mechanism to resolve files. The sass-loader uses node-sass' custom importer feature to pass all queries to the webpack resolving engine. Thus you can import your sass-modules from node_modules. Just prepend them with a ~ which tells webpack to look-up the modulesDirectories

@import "~bootstrap/less/bootstrap";

It's important to only prepend it with ~, because ~/ resolves to the home-directory. webpack needs to distinguish between bootstrap and ~bootstrap because CSS- and Sass-files have no special syntax for importing relative files. Writing @import "file" is the same as @import "./file";

For requiring .sass files, add indentedSyntax as a loader option:

module.exports = {
  module: {
    loaders: [
      {
        test: /\.sass$/,
        // Passing indentedSyntax query param to node-sass
        loader: "style!css!sass?indentedSyntax"
      }
    ]
  }
};

Because of browser limitations, source maps are only available in conjunction with the extract-text-webpack-plugin. Use that plugin to extract the CSS code from the generated JS bundle into a separate file (which even improves the perceived performance because JS and CSS are downloaded in parallel).

Then your webpack.config.js should look like this:

var ExtractTextPlugin = require('extract-text-webpack-plugin');

module.exports = {
    ...
    // must be 'source-map' or 'inline-source-map'
    devtool: 'source-map',
    module: {
        loaders: [
            {
                test: /\.scss$/,
                loader: ExtractTextPlugin.extract(
                    // activate source maps via loader query
                    'css?sourceMap!' +
                    'sass?sourceMap'
                )
            }
        ]
    },
    plugins: [
        // extract inline css into separate 'styles.css'
        new ExtractTextPlugin('styles.css')
    ]
};

If you want to view the original Sass files inside Chrome and even edit it, there's a good blog post. Checkout test/sourceMap for a running example. Make sure to serve the content with an HTTP server.

MIT (http://www.opensource.org/licenses/mit-license.php)