Webpack 4 support

__tests__/index.js

@@ -54,19 +54,20 @@ const prepareEntry = async (code, file) => {
 };
 
 const teardown = path => {
-  fs.readdir(path, (err, filenames) => {
-    filenames.forEach(file => {
+  const filenames = fs.readdirSync(path);
+  filenames.forEach(file => {
       const curPath = path + "/" + file;
       if (fs.lstatSync(curPath).isDirectory()) teardown(curPath);
       else fs.unlinkSync(curPath);
-    });
-    fs.rmdirSync(path);
   });
+
+  fs.rmdirSync(path);
 };
 
 describe("unit tests", () => {
   beforeAll(() => {
     if (!fs.existsSync("./temp")) fs.mkdirSync("./temp");
+    if (!fs.existsSync('./temp/ignored')) fs.mkdirSync('./temp/ignored');
   });
 
   afterAll(() => {
@@ -154,6 +155,7 @@ describe("unit tests", () => {
       bundle(
         {
           entry: entry,
+          mode: 'development',
           output: { filename: output },
           plugins: [new PrettierPlugin({ extensions: [".js"] })]
         },

index.js

@@ -39,38 +39,37 @@ module.exports = class PrettierPlugin {
   }
 
   apply(compiler) {
-    compiler.plugin("emit", (compilation, callback) => {
-      // Explore each chunk (build output):
-      compilation.chunks.forEach(chunk => {
-        // Explore each module within the chunk (built inputs):
-        chunk.modules.forEach(module => {
-          if (!module.fileDependencies) return;
+    compiler.hooks.emit.tapAsync('Prettier', (compilation, callback) => {
 
-          // Explore each source file path that was included into the module
-          module.fileDependencies.forEach(filepath => {
-            // If it matches
-            if (this.extensions.indexOf(path.extname(filepath)) !== -1) {
-              // Read the file
-              fs.readFile(filepath, this.encoding, (err, source) => {
-                // Format via prettier
-                var prettierSource = prettier.format(
-                  source,
-                  this.prettierOptions
-                );
+    const promises = [];
+    compilation.fileDependencies.forEach(filepath => {
+      if (this.extensions.indexOf(path.extname(filepath)) === -1) {
+        return;
+      }
 
-                // Rewrite file if prettier returned different source
-                if (prettierSource !== source) {
-                  fs.writeFile(filepath, prettierSource, this.encoding, err => {
-                    if (err) throw err;
-                  });
-                }
-              });
-            }
-          });
+      promises.push(new Promise((resolve, reject) => {
+        fs.readFile(filepath, this.encoding, (err, source) => {
+          if (err) {
+              return reject(err);
+          }
+          const prettierSource = prettier.format(source, this.prettierOptions);
+          if (prettierSource !== source) {
+            fs.writeFile(filepath, prettierSource, this.encoding, err => {
+              if (err) {
+                return reject(err);
+              }
+              resolve();
+            });
+          } else {
+            resolve();
+          }
         });
-      });
+      }));
+    });
 
-      callback();
+    Promise.all(promises).then(() => {
+        callback();
+      });
     });
   }
 };

package.json

@@ -9,6 +9,7 @@
     "ac:generate": "all-contributors generate"
   },
   "jest": {
+    "testEnvironment": "node",
     "testPathIgnorePatterns": [
       "sample-code.js"
     ]
@@ -32,10 +33,10 @@
     "prettier": "^1.0.0"
   },
   "devDependencies": {
-    "all-contributors-cli": "^4.3.0",
-    "jest": "^22.0.1",
+    "all-contributors-cli": "^4.11.1",
+    "jest": "^22.4.3",
     "prettier": "^1.0.0",
-    "uuid": "^3.0.1",
-    "webpack": "^3.1.0"
+    "uuid": "^3.2.1",
+    "webpack": "^4.2.0"
   }
 }