fix(index): continue watching after dependency {Error}

lib/index.js

@@ -186,6 +186,7 @@ module.exports = function loader (css, map) {
         return null
       })
   }).catch((err) => {
+    if (err.file) this.addDependency(err.file)
     return err.name === 'CssSyntaxError' ? cb(new SyntaxError(err)) : cb(err)
   })
 }

package.json

@@ -20,10 +20,12 @@
     "jest": "^21.0.0",
     "jsdoc-to-markdown": "^3.0.0",
     "memory-fs": "^0.4.0",
+    "postcss-import": "^11.0.0",
     "postcss-js": "^1.0.0",
     "standard": "^10.0.0",
     "standard-version": "^4.0.0",
     "sugarss": "^1.0.0",
+    "util.promisify": "^1.0.0",
     "webpack": "^3.0.0"
   },
   "scripts": {

test/__snapshots__/loader.test.js.snap

@@ -1,3 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`Loader Default 1`] = `"module.exports = \\"a { color: black }\\\\n\\""`;
+
+exports[`Loader Watching Dependencies Error 1`] = `"module.exports = \\"a { color: black }\\\\n\\""`;
+
+exports[`Loader Watching Dependencies Error 2`] = `"throw new Error(\\"Module build failed: Syntax Error \\\\n\\\\n(1:5) Unknown word\\\\n\\\\n\\\\u001b[31m\\\\u001b[1m>\\\\u001b[22m\\\\u001b[39m\\\\u001b[90m 1 | \\\\u001b[39ma \\\\u001b[33m{\\\\u001b[39m color black \\\\u001b[33m}\\\\u001b[39m\\\\n \\\\u001b[90m   | \\\\u001b[39m    \\\\u001b[31m\\\\u001b[1m^\\\\u001b[22m\\\\u001b[39m\\\\n \\\\u001b[90m 2 | \\\\u001b[39m\\\\n\\");"`;
+
+exports[`Loader Watching Dependencies Error 3`] = `"module.exports = \\"a { color: black }\\\\n\\""`;

test/fixtures/watch/watching/index.js

@@ -0,0 +1,3 @@
+import style from './style.css'
+
+export default style

test/fixtures/watch/watching/noSyntaxError.css

@@ -0,0 +1 @@
+a { color: black }

test/fixtures/watch/watching/style.css

@@ -0,0 +1 @@
+@import "./styleDep";

test/fixtures/watch/watching/syntaxError.css

@@ -0,0 +1 @@
+a { color black }

test/helpers/compiler.js

@@ -43,11 +43,21 @@ module.exports = function compiler (fixture, config, options) {
 
   if (!options.emit) compiler.outputFileSystem = new MemoryFS()
 
-  return new Promise((resolve, reject) => {
-    return compiler.run((err, stats) => {
-      if (err) reject(err)
+  if (options.watch) {
+    return new Promise((resolve, reject) => {
+      const watcher = compiler.watch({}, (err, stats) => {
+        options.watch(err, stats, (s) => {
+          watcher.close(resolve)
+        })
+      })
+    })
+  } else {
+    return new Promise((resolve, reject) => {
+      return compiler.run((err, stats) => {
+        if (err) reject(err)
 
-      resolve(stats)
+        resolve(stats)
+      })
     })
-  })
+  }
 }

test/helpers/fs.js

@@ -0,0 +1,33 @@
+const path = require('path')
+const { readFile: _readFile, writeFile: _writeFile, unlink: _unlink } = require('fs')
+const promisify = require('util.promisify')
+
+const fs = {
+  readFile: promisify(_readFile),
+  writeFile: promisify(_writeFile),
+  unlink: promisify(_unlink)
+}
+
+function readFile (name) {
+  const file = path.join(__dirname, '../fixtures', name)
+
+  return fs.readFile(file)
+    .then(data => data.toString())
+}
+
+function writeFile (name, contents) {
+  const file = path.join(__dirname, '../fixtures', name)
+
+  return fs.writeFile(file, contents)
+}
+
+module.exports.copyFile = function copyFile (src, dest) {
+  return readFile(src)
+    .then(contents => writeFile(dest, contents))
+}
+
+module.exports.deleteFile = function deleteFile (name) {
+  const file = path.join(__dirname, '../fixtures', name)
+
+  return fs.unlink(file)
+}

test/loader.test.js

@@ -2,6 +2,7 @@
 
 const webpack = require('./helpers/compiler')
 const { loader } = require('./helpers/compilation')
+const { copyFile, deleteFile } = require('./helpers/fs');
 
 describe('Loader', () => {
   test('Default', () => {
@@ -20,4 +21,67 @@ describe('Loader', () => {
         expect(src).toMatchSnapshot()
       })
   })
+
+  describe('Watching', () => {
+    describe('Dependencies', () => {
+      const files = {
+        syntaxError: "watch/watching/syntaxError.css",
+        noSyntaxError: "watch/watching/noSyntaxError.css",
+        changingFile: "watch/watching/styleDep.css"
+      }
+
+      beforeEach(() => copyFile(files.noSyntaxError, files.changingFile))
+
+      afterEach(() => deleteFile(files.changingFile))
+
+      test('Error', () => {
+        const config = {
+          loader: {
+            options: {
+              plugins: [require("postcss-import")],
+            }
+          }
+        }
+
+        const steps = [
+          (stats) => {
+            const { err, src } = loader(stats)
+
+            expect(src).toMatchSnapshot()
+            expect(err.length).toEqual(0)
+
+            return copyFile(files.syntaxError, files.changingFile)
+          },
+          (stats) => {
+            const { err, src } = loader(stats)
+
+            expect(src).toMatchSnapshot()
+            expect(err.length).toEqual(1)
+
+            return copyFile(files.noSyntaxError, files.changingFile)
+          },
+          (stats, close) => {
+            const { err, src } = loader(stats)
+
+            expect(src).toMatchSnapshot()
+            expect(src).toEqual("module.exports = \"a { color: black }\\n\"")
+            expect(err.length).toEqual(0)
+
+            return close()
+          }
+        ];
+
+        var currentStep = 0
+
+        const options = {
+          watch (err, stats, close) {
+            steps[currentStep](stats, close)
+            currentStep++
+          }
+        }
+
+        return webpack('watch/watching/index.js', config, options)
+      })
+    })
+  })
 })