[Fix] Prevent build from breaking when .scss file is empty (#1193)

packages/core/parcel-bundler/src/assets/LESSAsset.js

@@ -33,7 +33,7 @@ class LESSAsset extends Asset {
     return [
       {
         type: 'css',
-        value: this.ast.css,
+        value: this.ast ? this.ast.css : '',
         hasDependencies: false
       }
     ];

packages/core/parcel-bundler/src/assets/SASSAsset.js

@@ -48,7 +48,7 @@ class SASSAsset extends Asset {
     return [
       {
         type: 'css',
-        value: this.ast.css.toString(),
+        value: this.ast ? this.ast.css.toString() : '',
         hasDependencies: false
       }
     ];

packages/core/parcel-bundler/test/integration/less-empty/index.js

@@ -0,0 +1,5 @@
+require('./index.less');
+
+module.exports = function () {
+  return 2;
+};

packages/core/parcel-bundler/test/integration/scss-empty/index.js

@@ -0,0 +1,5 @@
+require('./index.scss');
+
+module.exports = function () {
+  return 2;
+};

packages/core/parcel-bundler/test/less.js

@@ -56,6 +56,32 @@ describe('less', function() {
     assert(css.includes('.base'));
   });
 
+  it('should support requiring empty less files', async function() {
+    let b = await bundle(__dirname + '/integration/less-empty/index.js');
+
+    assertBundleTree(b, {
+      name: 'index.js',
+      assets: ['index.js', 'index.less'],
+      childBundles: [
+        {
+          type: 'map'
+        },
+        {
+          name: 'index.css',
+          assets: ['index.less'],
+          childBundles: []
+        }
+      ]
+    });
+
+    let output = run(b);
+    assert.equal(typeof output, 'function');
+    assert.equal(output(), 2);
+
+    let css = fs.readFileSync(__dirname + '/dist/index.css', 'utf8');
+    assert.equal(css, '');
+  });
+
   it('should support linking to assets with url() from less', async function() {
     let b = await bundle(__dirname + '/integration/less-url/index.js');
 

packages/core/parcel-bundler/test/sass.js

@@ -82,6 +82,32 @@ describe('sass', function() {
     assert(css.includes('.base'));
   });
 
+  it('should support requiring empty scss files', async function() {
+    let b = await bundle(__dirname + '/integration/scss-empty/index.js');
+
+    assertBundleTree(b, {
+      name: 'index.js',
+      assets: ['index.js', 'index.scss'],
+      childBundles: [
+        {
+          type: 'map'
+        },
+        {
+          name: 'index.css',
+          assets: ['index.scss'],
+          childBundles: []
+        }
+      ]
+    });
+
+    let output = run(b);
+    assert.equal(typeof output, 'function');
+    assert.equal(output(), 2);
+
+    let css = fs.readFileSync(__dirname + '/dist/index.css', 'utf8');
+    assert.equal(css, '');
+  });
+
   it('should support linking to assets with url() from scss', async function() {
     let b = await bundle(__dirname + '/integration/scss-url/index.js');