fix(index): remove empty assets (#746)

Author: lili21

package-lock.json

@@ -33,6 +33,7 @@
   },
   "dependencies": {
     "async": "^2.4.1",
+    "glob": "^7.1.2",
     "loader-utils": "^1.1.0",
     "schema-utils": "^0.4.5",
     "webpack-sources": "^1.1.0"
@@ -65,7 +66,7 @@
     "raw-loader": "^0.5.1",
     "standard-version": "^4.3.0",
     "style-loader": "^0.19.1",
-    "webpack": "^4.0.0",
+    "webpack": "^4.1.1",
     "webpack-defaults": "^2.0.0-rc.4"
   },
   "engines": {

package.json

@@ -351,6 +351,10 @@ class ExtractTextPlugin {
               extractedChunk
             );
 
+            if (!source.size()) {
+              return;
+            }
+
             const getPath = (format) =>
               compilation
                 .getPath(format, {

src/index.js

@@ -42,6 +42,11 @@ c
 "
 `;
 
+exports[`Webpack Integration Tests empty-chunk 1`] = `
+"a
+"
+`;
+
 exports[`Webpack Integration Tests merging-chunk 1`] = `
 "a
 b
@@ -95,8 +100,6 @@ c
 "
 `;
 
-exports[`Webpack Integration Tests multiple-entries-filename 3`] = `""`;
-
 exports[`Webpack Integration Tests nested 1`] = `
 "a
 b

test/__snapshots__/webpack-integration.test.js.snap

@@ -0,0 +1,2 @@
+require('./a.txt');
+require('./b.txt');

test/cases/empty-chunk/a.js

@@ -0,0 +1 @@
+a

test/cases/empty-chunk/a.txt

@@ -0,0 +1,2 @@
+require('./b.txt');
+require('./c.txt');

test/cases/empty-chunk/b.js

@@ -0,0 +1 @@
+b

test/cases/empty-chunk/b.txt

@@ -0,0 +1 @@
+c

test/cases/empty-chunk/c.txt

@@ -0,0 +1 @@
+a

test/cases/empty-chunk/expected/main.css

@@ -0,0 +1,16 @@
+require('./a.txt');
+
+require.ensure(
+  [],
+  () => {
+    require('./a.js');
+  },
+  'async-chunk-a',
+);
+require.ensure(
+  [],
+  () => {
+    require('./b.js');
+  },
+  'async-chunk-b',
+);

test/cases/empty-chunk/index.js

@@ -0,0 +1,22 @@
+import ExtractTextPlugin from '../../../src/index';
+
+module.exports = {
+  entry: './index',
+  optimization: {
+    splitChunks: {
+      cacheGroups: {
+        common: {
+          name: 'common',
+          chunks: 'async',
+          test: /async-chunk-(a|b)/,
+        },
+      },
+    },
+    runtimeChunk: true
+  },
+  plugins: [
+    new ExtractTextPlugin({
+      filename: '[name].css'
+    }),
+  ],
+};

test/cases/empty-chunk/webpack.config.js

@@ -6,6 +6,7 @@
 import fs from 'fs';
 import path from 'path';
 import webpack from 'webpack';
+import glob from 'glob';
 import ExtractTextPlugin from '../src';
 
 const cases = process.env.CASES
@@ -47,24 +48,20 @@ describe('Webpack Integration Tests', () => {
           require(testFile)(suite);
         }
         const expectedDirectory = path.join(testDirectory, 'expected');
-        fs.readdirSync(expectedDirectory).forEach((file) => {
-          const filePath = path.join(expectedDirectory, file);
-          const actualPath = path.join(outputDirectory, file);
-          expect(readFileOrEmpty(actualPath)).toEqual(
-            readFileOrEmpty(filePath)
-          );
-          expect(readFileOrEmpty(actualPath)).toMatchSnapshot();
-        });
+
+        glob
+          .sync('**/*.@(txt|css)', { cwd: outputDirectory })
+          .forEach((file) => {
+            const filePath = path.join(expectedDirectory, file);
+            const actualPath = path.join(outputDirectory, file);
+            expect(fs.existsSync(filePath)).toBeTruthy();
+            expect(fs.readFileSync(actualPath, 'utf-8')).toEqual(
+              fs.readFileSync(filePath, 'utf-8')
+            );
+            expect(fs.readFileSync(actualPath, 'utf-8')).toMatchSnapshot();
+          });
         done();
       });
     });
   });
 });
-
-function readFileOrEmpty(filePath) {
-  try {
-    return fs.readFileSync(filePath, 'utf-8');
-  } catch (e) {
-    return '';
-  }
-}