Implement Sass loader to react-scripts webpack config

Author: ehaivala

packages/react-scripts/config/webpack.config.dev.js

@@ -183,13 +183,15 @@ module.exports = {
                 loader: require.resolve('css-loader'),
                 options: {
                   importLoaders: 1,
+                  sourceMap: true,
                 },
               },
               {
                 loader: require.resolve('postcss-loader'),
                 options: {
                   // Necessary for external CSS imports to work
                   // https://github.com/facebookincubator/create-react-app/issues/2677
+                  sourceMap: true,
                   ident: 'postcss',
                   plugins: () => [
                     require('postcss-flexbugs-fixes'),
@@ -207,6 +209,47 @@ module.exports = {
               },
             ],
           },
+          {
+            test: /\.(sass|scss)$/,
+            fallback: require.resolve('style-loader'),
+            use: [
+              require.resolve('style-loader'),
+              {
+                loader: require.resolve('css-loader'),
+                options: {
+                  importLoaders: 1,
+                  sourceMap: true,
+                },
+              },
+              {
+                loader: require.resolve('postcss-loader'),
+                options: {
+                  // Necessary for external CSS imports to work
+                  // https://github.com/facebookincubator/create-react-app/issues/2677
+                  sourceMap: true,
+                  ident: 'postcss',
+                  plugins: () => [
+                    require('postcss-flexbugs-fixes'),
+                    autoprefixer({
+                      browsers: [
+                        '>1%',
+                        'last 4 versions',
+                        'Firefox ESR',
+                        'not ie < 9', // React doesn't support IE8 anyway
+                      ],
+                      flexbox: 'no-2009',
+                    }),
+                  ],
+                },
+              },
+              {
+                loader: require.resolve('sass-loader'),
+                options: {
+                  sourceMap: true,
+                },
+              },
+            ],
+          },
           // "file" loader makes sure those assets get served by WebpackDevServer.
           // When you `import` an asset, you get its (virtual) filename.
           // In production, they would get copied to the `build` folder.

packages/react-scripts/config/webpack.config.prod.js

@@ -227,6 +227,54 @@ module.exports = {
             ),
             // Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
           },
+          {
+            test: /\.(sass|scss)$/,
+            loader: ExtractTextPlugin.extract(
+              Object.assign(
+                {
+                  fallback: require.resolve('style-loader'),
+                  use: [
+                    {
+                      loader: require.resolve('css-loader'),
+                      options: {
+                        importLoaders: 1,
+                        minimize: true,
+                        sourceMap: shouldUseSourceMap,
+                      },
+                    },
+                    {
+                      loader: require.resolve('postcss-loader'),
+                      options: {
+                        // Necessary for external CSS imports to work
+                        // https://github.com/facebookincubator/create-react-app/issues/2677
+                        ident: 'postcss',
+                        plugins: () => [
+                          require('postcss-flexbugs-fixes'),
+                          autoprefixer({
+                            browsers: [
+                              '>1%',
+                              'last 4 versions',
+                              'Firefox ESR',
+                              'not ie < 9', // React doesn't support IE8 anyway
+                            ],
+                            flexbox: 'no-2009',
+                          }),
+                        ],
+                      },
+                    },
+                    {
+                      loader: require.resolve('sass-loader'),
+                      options: {
+                        sourceMap: shouldUseSourceMap,
+                      },
+                    },
+                  ],
+                },
+                extractTextPluginOptions
+              )
+            ),
+            // Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
+          },
           // "file" loader makes sure assets end up in the `build` folder.
           // When you `import` an asset, you get its filename.
           // This loader don't uses a "test" so it will catch all modules

packages/react-scripts/package.json

@@ -31,11 +31,13 @@
     "fs-extra": "3.0.1",
     "html-webpack-plugin": "2.29.0",
     "jest": "20.0.4",
+    "node-sass": "^4.5.3",
     "object-assign": "4.1.1",
     "postcss-flexbugs-fixes": "3.2.0",
     "postcss-loader": "2.0.6",
     "promise": "8.0.1",
     "react-dev-utils": "^4.0.1",
+    "sass-loader": "^6.0.6",
     "style-loader": "0.18.2",
     "ts-jest": "^20.0.7",
     "ts-loader": "^2.2.1",