fix: re-emit error when bundling

Author: SimenB

lib/writer.js

@@ -69,13 +69,17 @@ module.exports = class Writer extends EventEmitter {
             return cssStream;
         }
 
-        return cssStream.pipe(
-            new Transform({
-                objectMode: true,
-                transform(chunk, enc, next) {
-                    next(null, chunk.content);
-                },
-            })
+        const transformStream = new Transform({
+            objectMode: true,
+            transform(chunk, enc, next) {
+                next(null, chunk.content);
+            },
+        });
+
+        cssStream.on('error', (...args) =>
+            transformStream.emit('error', ...args)
         );
+
+        return cssStream.pipe(transformStream);
     }
 };

test/__snapshots__/writer.test.js.snap

@@ -13,3 +13,10 @@ exports[`new Writer([filePath]) ensures valid filePath provided 1`] = `"Expected
 exports[`new Writer([filePath]) ensures valid filePaths provided in array 1`] = `"Expected 'file' (fake.css) to be an absolute path to a file but it was not"`;
 
 exports[`new Writer(filePath) relative paths throw error 1`] = `"Expected 'file' (./test-assets/my-module-1/main.css) to be an absolute path to a file but it was not"`;
+
+exports[`underlying writer error bubbles up 1`] = `
+"Failed to find 'some-random-file.css'
+  in [
+    <root>/test-assets
+  ]"
+`;

test/test-assets/bogus.css

@@ -0,0 +1 @@
+@import "~some-random-file.css";

test/writer.test.js

@@ -6,11 +6,18 @@ const { hasher } = require('@asset-pipe/common');
 const { identifyCssModule, bundleCssModule } = require('../lib/util.js');
 const Writer = require('..');
 
-beforeEach(() => {
-    jest.clearAllMocks();
+afterEach(() => {
+    jest.unmock('../lib/util.js');
     jest.resetModules();
 });
 
+function clean(message) {
+    return message
+        .split('\n')
+        .map(line => line.replace(__dirname, '<root>'))
+        .join('\n');
+}
+
 test('identifyCssModule(filePath)', async () => {
     expect.assertions(1);
     const filePath = path.join(__dirname, 'test-assets/my-module-1/main.css');
@@ -262,6 +269,20 @@ test('writer emits error', done => {
     writer.on('data', () => {});
 });
 
+test('underlying writer error bubbles up', done => {
+    expect.assertions(1);
+    const CssWriter = require('..');
+    const filePath = path.join(__dirname, 'test-assets/bogus.css');
+
+    const writer = new CssWriter(filePath, true).bundle();
+
+    writer.on('error', error => {
+        expect(clean(error.message)).toMatchSnapshot();
+        done();
+    });
+    writer.on('data', () => {});
+});
+
 test('new Writer() emits nothing but does not break', done => {
     const writer = new Writer().bundle();
     const items = [];