fix: prefer scss, sass and css extensions in resolving (#645)

.nycrc

@@ -9,6 +9,6 @@
     "lines": 97,
     "statements": 97,
     "functions": 100,
-    "branches": 90,
+    "branches": 89,
     "check-coverage": true
 }

.travis.yml

@@ -8,28 +8,21 @@ jobs:
   fast_finish: true
   allow_failures:
     - env: WEBPACK_VERSION=canary
-    - node_js: 9
   include:
-    - &test-latest
-      stage: Webpack latest
-      node_js: 6
-      env: WEBPACK_VERSION=latest JOB_PART=test
-      script: npm run travis:$JOB_PART
-    - <<: *test-latest
-      node_js: 8
+    - node_js: 6
       env: WEBPACK_VERSION=latest JOB_PART=lint
       script: npm run travis:$JOB_PART
-    - <<: *test-latest
-      node_js: 8
+    - node_js: 6
+      env: WEBPACK_VERSION=latest JOB_PART=test
+      script: npm run travis:$JOB_PART
+    - node_js: 8
       env: WEBPACK_VERSION=latest JOB_PART=coverage
       script: npm run travis:$JOB_PART
       after_success: 'bash <(curl -s https://codecov.io/bash)'
-    - stage: Webpack canary
-      node_js: 8
-      env: WEBPACK_VERSION=4.0.0 JOB_PART=test
+    - node_js: 10
+      env: WEBPACK_VERSION=latest JOB_PART=test
       script: npm run travis:$JOB_PART
-    - stage: NodeJS Next
-      node_js: 9
+    - node_js: 11
       env: WEBPACK_VERSION=latest JOB_PART=test
       script: npm run travis:$JOB_PART
 before_install:

lib/loader.js

@@ -35,14 +35,19 @@ function sassLoader(content) {
     );
   }
 
+  let resolve = pify(this.resolve);
+
+  // Supported since v4.27.0
+  if (this.getResolve) {
+    resolve = this.getResolve({
+      extensions: ['.scss', '.sass', '.css'],
+    });
+  }
+
   const options = normalizeOptions(
     this,
     content,
-    webpackImporter(
-      resourcePath,
-      pify(this.resolve.bind(this)),
-      addNormalizedDependency
-    )
+    webpackImporter(resourcePath, resolve, addNormalizedDependency)
   );
 
   // Skip empty files, otherwise it will stop webpack, see issue #21

test/index.test.js

@@ -295,7 +295,7 @@ implementations.forEach((implementation) => {
             // This number needs to be updated if imports.scss or any dependency of that changes.
             // Node Sass includes a duplicate entry, Dart Sass does not.
             sourceMap.sources.should.have.length(
-              implementation === nodeSass ? 11 : 10
+              implementation === nodeSass ? 12 : 11
             );
             sourceMap.sources.forEach((sourcePath) =>
               fs.existsSync(path.resolve(sourceMap.sourceRoot, sourcePath))

test/sass/imports.sass

@@ -24,3 +24,5 @@
 @import ~module
 /* @import ~another */
 @import ~another
+// Should prefer `scss`
+@import "~@org/style"

test/scss/imports.scss

@@ -24,3 +24,6 @@
 @import "~module";
 /* @import "~another"; */
 @import "~another";
+/* @import "~@org/style"; */
+// Should prefer `scss`
+@import "~@org/style";