feat: issue-#150 - Ignore empty files and css file support

- Cleaned up related fixtures.
- Updated 'watch' feature tests to also include
  'empty files' case promise test.

Author: elycruz

src/index.ts

@@ -194,19 +194,15 @@ export = function plugin(options = {} as RollupPluginSassOptions): RollupPlugin
           .then(result => [res, result])
         )
         .then(([res, codeResult]) => {
-
-          if (!codeResult) return null;
-
             // @todo Do we need to filter this call so it only occurs when rollup is in 'watch' mode?
-            res.stats.includedFiles.forEach(filePath => {
+            res.stats.includedFiles.forEach((filePath: string) => {
               this.addWatchFile(filePath);
             });
 
             return {
-                code: codeResult,
+                code: codeResult || '',
                 map: {mappings: res.map ? res.map.toString() : ''}
             };
-
         }); // @note do not `catch` here - let error propagate to rollup level.
     },
 

test/fixtures/dependencies/empty-style3.css renamed to test/fixtures/dependencies/empty-style3.scss

@@ -1,3 +1,4 @@
 import style1 from './style1.scss';
+import emptyStyle1 from './empty-style1.scss';
 
 export default style1;

test/fixtures/dependencies/index.js

@@ -1,3 +1,4 @@
-@import 'style2.scss';
+@import './style2.sass';
+@import './empty-style2.sass';
 
 body {color: red;}

test/fixtures/dependencies/index.should-ignore-empties.js

@@ -1,4 +1,5 @@
-@import 'style3.scss'
+@import './style3.scss'
+@import './empty-style3'
 
 body
   color: white