feat: webpackImporter option (#732)

README.md

@@ -346,6 +346,39 @@ module.exports = {
 
 > ℹ In some rare case `node-sass` can output invalid source maps (it is `node-sass` bug), to avoid try to update node-sass to latest version or you can try to set the `outputStyle` option to `compressed` value.
 
+### `webpackImporter`
+
+Type: `Boolean`
+Default: `true`
+
+Allows to disable default `webpack` importer.
+
+This can improve performance in some cases. Use it with caution because aliases and `@import` at-rules starts with `~` will not work, but you can pass own `importer` to solve this (see [`importer docs`](https://github.com/sass/node-sass#importer--v200---experimental)).
+
+**webpack.config.js**
+
+```js
+module.exports = {
+  module: {
+    rules: [
+      {
+        test: /\.s[ac]ss$/i,
+        use: [
+          'style-loader',
+          'css-loader',
+          {
+            loader: 'sass-loader',
+            options: {
+              webpackImporter: false,
+            },
+          },
+        ],
+      },
+    ],
+  },
+};
+```
+
 ## Examples
 
 ### Extracts CSS into separate files

src/index.js

@@ -62,9 +62,16 @@ function loader(content) {
 
   const sassOptions = getSassOptions(this, options, content);
 
-  sassOptions.importer.push(
-    webpackImporter(this.resourcePath, resolve, addNormalizedDependency)
-  );
+  const shouldUseWebpackImporter =
+    typeof options.webpackImporter === 'boolean'
+      ? options.webpackImporter
+      : true;
+
+  if (shouldUseWebpackImporter) {
+    sassOptions.importer.push(
+      webpackImporter(this.resourcePath, resolve, addNormalizedDependency)
+    );
+  }
 
   // Skip empty files, otherwise it will stop webpack, see issue #21
   if (sassOptions.data.trim() === '') {

test/__snapshots__/webpackImporter-options.test.js.snap

@@ -0,0 +1,49 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`webpackImporter option false (dart-sass) (sass): errors 1`] = `Array []`;
+
+exports[`webpackImporter option false (dart-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option false (dart-sass) (scss): errors 1`] = `Array []`;
+
+exports[`webpackImporter option false (dart-sass) (scss): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option false (node-sass) (sass): errors 1`] = `Array []`;
+
+exports[`webpackImporter option false (node-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option false (node-sass) (scss): errors 1`] = `Array []`;
+
+exports[`webpackImporter option false (node-sass) (scss): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (dart-sass) (sass): errors 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (dart-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (dart-sass) (scss): errors 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (dart-sass) (scss): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (node-sass) (sass): errors 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (node-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (node-sass) (scss): errors 1`] = `Array []`;
+
+exports[`webpackImporter option not specify (node-sass) (scss): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option true (dart-sass) (sass): errors 1`] = `Array []`;
+
+exports[`webpackImporter option true (dart-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option true (dart-sass) (scss): errors 1`] = `Array []`;
+
+exports[`webpackImporter option true (dart-sass) (scss): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option true (node-sass) (sass): errors 1`] = `Array []`;
+
+exports[`webpackImporter option true (node-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`webpackImporter option true (node-sass) (scss): errors 1`] = `Array []`;
+
+exports[`webpackImporter option true (node-sass) (scss): warnings 1`] = `Array []`;

test/webpackImporter-options.test.js

@@ -0,0 +1,71 @@
+/**
+ * @jest-environment node
+ */
+import nodeSass from 'node-sass';
+import dartSass from 'sass';
+
+import {
+  compile,
+  getTestId,
+  getCodeFromBundle,
+  getCodeFromSass,
+  getImplementationByName,
+} from './helpers';
+
+const implementations = [nodeSass, dartSass];
+const syntaxStyles = ['scss', 'sass'];
+
+describe('webpackImporter option', () => {
+  implementations.forEach((implementation) => {
+    syntaxStyles.forEach((syntax) => {
+      const [implementationName] = implementation.info.split('\t');
+
+      it(`not specify (${implementationName}) (${syntax})`, async () => {
+        const testId = getTestId('language', syntax);
+        const options = {
+          implementation: getImplementationByName(implementationName),
+        };
+        const stats = await compile(testId, { loader: { options } });
+
+        expect(getCodeFromBundle(stats).css).toBe(
+          getCodeFromSass(testId, options).css
+        );
+
+        expect(stats.compilation.warnings).toMatchSnapshot('warnings');
+        expect(stats.compilation.errors).toMatchSnapshot('errors');
+      });
+
+      it(`false (${implementationName}) (${syntax})`, async () => {
+        const testId = getTestId('language', syntax);
+        const options = {
+          webpackImporter: false,
+          implementation: getImplementationByName(implementationName),
+        };
+        const stats = await compile(testId, { loader: { options } });
+
+        expect(getCodeFromBundle(stats).css).toBe(
+          getCodeFromSass(testId, options).css
+        );
+
+        expect(stats.compilation.warnings).toMatchSnapshot('warnings');
+        expect(stats.compilation.errors).toMatchSnapshot('errors');
+      });
+
+      it(`true (${implementationName}) (${syntax})`, async () => {
+        const testId = getTestId('language', syntax);
+        const options = {
+          webpackImporter: true,
+          implementation: getImplementationByName(implementationName),
+        };
+        const stats = await compile(testId, { loader: { options } });
+
+        expect(getCodeFromBundle(stats).css).toBe(
+          getCodeFromSass(testId, options).css
+        );
+
+        expect(stats.compilation.warnings).toMatchSnapshot('warnings');
+        expect(stats.compilation.errors).toMatchSnapshot('errors');
+      });
+    });
+  });
+});