feat(index): add noImporter option (options.noImporter)

README.md

@@ -104,6 +104,13 @@ Alternatively, for bootstrap-sass:
 
 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";`
 
+### Disabling imports for faster compile time
+
+Function calls associated with the advanced file resolution described above can add up to a significant time on projects with a large number of scss files.
+E.g. on a project with some 130 components each requiring an .scss file, sass build took 240 seconds with the importer, and 3 seconds without. To disable the
+advanced import resolution, pass `noImporter: true` in the `sassLoader` options.
+
+
 ### Environment variables
 
 If you want to prepend Sass code before the actual entry file, you can simply set the `data` option. In this case, the sass-loader will not override the `data` option but just append the entry's content. This is especially useful when some of your Sass variables depend on the environment:

index.js

@@ -249,6 +249,12 @@ module.exports = function (content) {
     sassOptions.importer = sassOptions.importer ? proxyCustomImporters(sassOptions.importer, resourcePath) : [];
     sassOptions.importer.push(getWebpackImporter());
 
+    // For larger projects, using the webpack importer can really add up: 4 minutes versus 3 seconds on a
+    // modest project with a 130 components and a dozen common definition files required in each scss file
+    if (sassOptions.noImporter === true) {
+        sassOptions.importer = undefined;
+    }
+
     // `node-sass` uses `includePaths` to resolve `@import` paths. Append the currently processed file.
     sassOptions.includePaths = sassOptions.includePaths ? [].concat(sassOptions.includePaths) : [];
     sassOptions.includePaths.push(path.dirname(resourcePath));