fix: resolution logic (#830)

src/index.js

@@ -36,7 +36,7 @@ function loader(content) {
     const resolve = this.getResolve({
       mainFields: ['sass', 'style', 'main', '...'],
       mainFiles: ['_index', 'index', '...'],
-      extensions: ['.scss', '.sass', '.css', '...'],
+      extensions: ['.scss', '.sass', '.css'],
     });
 
     const includePaths =

test/__snapshots__/loader.test.js.snap

@@ -1,5 +1,45 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`loader should load only sass/scss files for the "mainFiles" (dart-sass) (sass): css 1`] = `
+"a {
+  color: red;
+}"
+`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (dart-sass) (sass): errors 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (dart-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (dart-sass) (scss): css 1`] = `
+"a {
+  color: red;
+}"
+`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (dart-sass) (scss): errors 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (dart-sass) (scss): warnings 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (node-sass) (sass): css 1`] = `
+"a {
+  color: red; }
+"
+`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (node-sass) (sass): errors 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (node-sass) (sass): warnings 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (node-sass) (scss): css 1`] = `
+"a {
+  color: red; }
+"
+`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (node-sass) (scss): errors 1`] = `Array []`;
+
+exports[`loader should load only sass/scss files for the "mainFiles" (node-sass) (scss): warnings 1`] = `Array []`;
+
 exports[`loader should output an understandable error (dart-sass) (sass): errors 1`] = `
 Array [
   "ModuleBuildError: Module build failed (from ../src/cjs.js):

test/helpers/getCodeFromSass.js

@@ -248,6 +248,10 @@ function getCodeFromSass(testId, options) {
         testFolder,
         'node_modules/package-with-style-field-and-css/scss/package-with-style-field-and-css.scss'
       );
+  const pathToPackageWithJsAndCssMainFiles = path.resolve(
+    testFolder,
+    'node_modules/package-with-js-and-css-main-files/index'
+  );
 
   // Pseudo importer for tests
   function testImporter(url) {
@@ -690,6 +694,10 @@ function getCodeFromSass(testId, options) {
         .replace(/^~bootstrap$/, pathToBootstrap4Entry)
         .replace(/^~module/, pathToModule)
         .replace(/^~another/, pathToAnother)
+        .replace(
+          /^~package-with-js-and-css-main-files/,
+          pathToPackageWithJsAndCssMainFiles
+        )
         .replace(/^~/, testNodeModules);
     }
 

test/loader.test.js

@@ -620,6 +620,25 @@ describe('loader', () => {
         expect(getErrors(stats)).toMatchSnapshot('errors');
       });
 
+      it(`should load only sass/scss files for the "mainFiles" (${implementationName}) (${syntax})`, async () => {
+        const testId = getTestId(
+          'import-package-with-js-and-css-main-files',
+          syntax
+        );
+        const options = {
+          implementation: getImplementationByName(implementationName),
+        };
+        const compiler = getCompiler(testId, { loader: { options } });
+        const stats = await compile(compiler);
+        const codeFromBundle = getCodeFromBundle(stats, compiler);
+        const codeFromSass = getCodeFromSass(testId, options);
+
+        expect(codeFromBundle.css).toBe(codeFromSass.css);
+        expect(codeFromBundle.css).toMatchSnapshot('css');
+        expect(getWarnings(stats)).toMatchSnapshot('warnings');
+        expect(getErrors(stats)).toMatchSnapshot('errors');
+      });
+
       if (implementation === dartSass) {
         it(`should output an understandable error with a problem in "@use" (${implementationName}) (${syntax})`, async () => {
           const testId = getTestId('error-use', syntax);

test/sass/import-package-with-js-and-css-main-files.sass

@@ -0,0 +1 @@
+@import "~package-with-js-and-css-main-files"

test/scss/import-package-with-js-and-css-main-files.scss

@@ -0,0 +1 @@
+@import "~package-with-js-and-css-main-files";