@format JSTransformer

Reviewed By: jeanlauliac

Differential Revision: D5208868

fbshipit-source-id: 3b80197c4e879974f9129ccfc4e4a7ca7d4b4258

packages/metro-bundler/src/JSTransformer/__mocks__/lodash.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 

packages/metro-bundler/src/JSTransformer/__mocks__/worker.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 

packages/metro-bundler/src/JSTransformer/__tests__/Transformer-test.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 
@@ -34,48 +36,68 @@ describe('Transformer', function() {
     fs.writeFileSync.mockClear();
     workerFarm.mockClear();
     workerFarm.mockImplementation((opts, path, methods) => {
-      const api = workers = {};
-      methods.forEach(method => {api[method] = jest.fn();});
-      return {methods: api, stdout: new Readable({read() {}}), stderr: new Readable({read() {}})};
+      const api = (workers = {});
+      methods.forEach(method => {
+        api[method] = jest.fn();
+      });
+      return {
+        methods: api,
+        stdout: new Readable({read() {}}),
+        stderr: new Readable({read() {}}),
+      };
     });
   });
 
-  it('passes transform module path, file path, source code' +
-    ' to the worker farm when transforming', () => {
-    const transformOptions = {arbitrary: 'options'};
-    const code = 'arbitrary(code)';
-    new Transformer(transformModulePath).transformFile(fileName, localPath, code, transformOptions);
-    expect(workers.transformAndExtractDependencies).toBeCalledWith(
-      transformModulePath,
-      fileName,
-      localPath,
-      code,
-      transformOptions,
-      any(Function),
-    );
-  });
+  it(
+    'passes transform module path, file path, source code' +
+      ' to the worker farm when transforming',
+    () => {
+      const transformOptions = {arbitrary: 'options'};
+      const code = 'arbitrary(code)';
+      new Transformer(transformModulePath).transformFile(
+        fileName,
+        localPath,
+        code,
+        transformOptions,
+      );
+      expect(workers.transformAndExtractDependencies).toBeCalledWith(
+        transformModulePath,
+        fileName,
+        localPath,
+        code,
+        transformOptions,
+        any(Function),
+      );
+    },
+  );
 
   it('should add file info to parse errors', function() {
     const transformer = new Transformer(transformModulePath);
     var message = 'message';
     var snippet = 'snippet';
 
-    workers.transformAndExtractDependencies.mockImplementation(
-      function(transformPath, filename, localPth, code, opts, callback) {
-        var babelError = new SyntaxError(message);
-        babelError.type = 'SyntaxError';
-        babelError.description = message;
-        babelError.loc = {
-          line: 2,
-          column: 15,
-        };
-        babelError.codeFrame = snippet;
-        callback(babelError);
-      },
-    );
+    workers.transformAndExtractDependencies.mockImplementation(function(
+      transformPath,
+      filename,
+      localPth,
+      code,
+      opts,
+      callback,
+    ) {
+      var babelError = new SyntaxError(message);
+      babelError.type = 'SyntaxError';
+      babelError.description = message;
+      babelError.loc = {
+        line: 2,
+        column: 15,
+      };
+      babelError.codeFrame = snippet;
+      callback(babelError);
+    });
 
     expect.assertions(7);
-    return transformer.transformFile(fileName, localPath, '', {})
+    return transformer
+      .transformFile(fileName, localPath, '', {})
       .catch(function(error) {
         expect(error.type).toEqual('TransformError');
         expect(error.message).toBe('SyntaxError ' + message);

packages/metro-bundler/src/JSTransformer/index.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';
@@ -23,12 +24,18 @@ const workerFarm = require('../worker-farm');
 import type {Data as TransformData, Options as WorkerOptions} from './worker';
 import type {LocalPath} from '../node-haste/lib/toLocalPath';
 import type {MappingsMap} from '../lib/SourceMap';
-import typeof {minify as Minify, transformAndExtractDependencies as TransformAndExtractDependencies} from './worker';
+import typeof {
+  minify as Minify,
+  transformAndExtractDependencies as TransformAndExtractDependencies,
+} from './worker';
 
 type CB<T> = (?Error, ?T) => mixed;
-type Denodeify =
-  & (<A, B, C, T>((A, B, C, CB<T>) => void) => (A, B, C) => Promise<T>)
-  & (<A, B, C, D, E, T>((A, B, C, D, E, CB<T>) => void) => (A, B, C, D, E) => Promise<T>);
+type Denodeify = (<A, B, C, T>(
+  (A, B, C, CB<T>) => void,
+) => (A, B, C) => Promise<T>) &
+  (<A, B, C, D, E, T>(
+    (A, B, C, D, E, CB<T>) => void,
+  ) => (A, B, C, D, E) => Promise<T>);
 
 // Avoid memory leaks caused in workers. This number seems to be a good enough number
 // to avoid any memory leak while not slowing down initial builds.
@@ -63,7 +70,6 @@ type Reporters = {
 };
 
 class Transformer {
-
   _workers: {[name: string]: Function};
   _transformModulePath: string;
   _transform: (
@@ -85,7 +91,10 @@ class Transformer {
     reporters: Reporters,
     workerPath: ?string,
   ) {
-    invariant(path.isAbsolute(transformModulePath), 'transform module path should be absolute');
+    invariant(
+      path.isAbsolute(transformModulePath),
+      'transform module path should be absolute',
+    );
     this._transformModulePath = transformModulePath;
 
     const farm = makeFarm(
@@ -102,7 +111,10 @@ class Transformer {
     });
 
     this._workers = farm.methods;
-    this._transform = denodeify((this._workers.transformAndExtractDependencies: TransformAndExtractDependencies));
+    this._transform = denodeify(
+      (this._workers
+        .transformAndExtractDependencies: TransformAndExtractDependencies),
+    );
     this.minify = denodeify((this._workers.minify: Minify));
   }
 
@@ -114,19 +126,19 @@ class Transformer {
     fileName: string,
     localPath: LocalPath,
     code: string,
-    options: WorkerOptions) {
+    options: WorkerOptions,
+  ) {
     if (!this._transform) {
       return Promise.reject(new Error('No transform module'));
     }
     debug('transforming file', fileName);
-    return this
-      ._transform(
-        this._transformModulePath,
-        fileName,
-        localPath,
-        code,
-        options,
-      )
+    return this._transform(
+      this._transformModulePath,
+      fileName,
+      localPath,
+      code,
+      options,
+    )
       .then(data => {
         Logger.log(data.transformFileStartLogEntry);
         Logger.log(data.transformFileEndLogEntry);
@@ -137,8 +149,8 @@ class Transformer {
         if (error.type === 'TimeoutError') {
           const timeoutErr = new Error(
             `TimeoutError: transforming ${fileName} took longer than ` +
-            `${TRANSFORM_TIMEOUT_INTERVAL / 1000} seconds.\n` +
-            'You can adjust timeout via the \'transformTimeoutInterval\' option'
+              `${TRANSFORM_TIMEOUT_INTERVAL / 1000} seconds.\n` +
+              "You can adjust timeout via the 'transformTimeoutInterval' option",
           );
           /* $FlowFixMe: monkey-patch Error */
           timeoutErr.type = 'TimeoutError';
@@ -146,7 +158,7 @@ class Transformer {
         } else if (error.type === 'ProcessTerminatedError') {
           const uncaughtError = new Error(
             'Uncaught error in the transformer worker: ' +
-            this._transformModulePath
+              this._transformModulePath,
           );
           /* $FlowFixMe: monkey-patch Error */
           uncaughtError.type = 'ProcessTerminatedError';

packages/metro-bundler/src/JSTransformer/worker/JsMinification.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';

packages/metro-bundler/src/JSTransformer/worker/__tests__/constant-folding-test.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 
@@ -38,18 +40,19 @@ describe('constant expressions', () => {
         'foo'==='bar' ? b : c,
         f() ? g() : h()
       );`;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('a(true,true,2,true,{},{a:1},c,f()?g():h());');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual(
+      'a(true,true,2,true,{},{a:1},c,f()?g():h());',
+    );
   });
 
   it('can optimize ternary expressions with constant conditions', () => {
-    const code =
-      `var a = true ? 1 : 2;
+    const code = `var a = true ? 1 : 2;
        var b = 'android' == 'android'
          ? ('production' != 'production' ? 'a' : 'A')
          : 'i';`;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('var a=1;var b=\'A\';');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual(
+      "var a=1;var b='A';",
+    );
   });
 
   it('can optimize logical operator expressions with constant conditions', () => {
@@ -57,8 +60,9 @@ describe('constant expressions', () => {
       var a = true || 1;
       var b = 'android' == 'android' &&
         'production' != 'production' || null || "A";`;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('var a=true;var b="A";');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual(
+      'var a=true;var b="A";',
+    );
   });
 
   it('can optimize logical operators with partly constant operands', () => {
@@ -69,8 +73,9 @@ describe('constant expressions', () => {
       var d = null || z();
       var e = !1 && z();
     `;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('var a="truthy";var b=z();var c=null;var d=z();var e=false;');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual(
+      'var a="truthy";var b=z();var c=null;var d=z();var e=false;',
+    );
   });
 
   it('can remode an if statement with a falsy constant test', () => {
@@ -79,8 +84,7 @@ describe('constant expressions', () => {
         var a = 1;
       }
     `;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual('');
   });
 
   it('can optimize if-else-branches with constant conditions', () => {
@@ -95,8 +99,9 @@ describe('constant expressions', () => {
         var a = 'b';
       }
     `;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('{var a=3;var b=a+4;}');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual(
+      '{var a=3;var b=a+4;}',
+    );
   });
 
   it('can optimize nested if-else constructs', () => {
@@ -115,7 +120,8 @@ describe('constant expressions', () => {
         }
       }
     `;
-    expect(normalize(constantFolding('arbitrary.js', parse(code))))
-      .toEqual('{{require(\'c\');}}');
+    expect(normalize(constantFolding('arbitrary.js', parse(code)))).toEqual(
+      "{{require('c');}}",
+    );
   });
 });

packages/metro-bundler/src/JSTransformer/worker/__tests__/extract-dependencies-test.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 
@@ -22,8 +24,7 @@ describe('Dependency extraction:', () => {
       require
       ('more');`;
     const {dependencies, dependencyOffsets} = extractDependencies(code);
-    expect(dependencies)
-      .toEqual(['foo/bar', 'React', 'Component', 'more']);
+    expect(dependencies).toEqual(['foo/bar', 'React', 'Component', 'more']);
     expect(dependencyOffsets).toEqual([8, 46, 147, 203]);
   });
 
@@ -76,7 +77,7 @@ describe('Dependency extraction:', () => {
   });
 
   it('does not extract calls to function with names that start with "require"', () => {
-    const code = 'arbitraryrequire(\'foo\');';
+    const code = "arbitraryrequire('foo');";
 
     const {dependencies, dependencyOffsets} = extractDependencies(code);
     expect(dependencies).toEqual([]);
@@ -84,7 +85,7 @@ describe('Dependency extraction:', () => {
   });
 
   it('does not extract calls to require with non-static arguments', () => {
-    const code = 'require(\'foo/\' + bar)';
+    const code = "require('foo/' + bar)";
 
     const {dependencies, dependencyOffsets} = extractDependencies(code);
     expect(dependencies).toEqual([]);
@@ -101,7 +102,7 @@ describe('Dependency extraction:', () => {
   });
 
   it('can handle regular expressions', () => {
-    const code = 'require(\'a\'); /["\']/.test(\'foo\'); require("b");';
+    const code = "require('a'); /[\"']/.test('foo'); require(\"b\");";
 
     const {dependencies, dependencyOffsets} = extractDependencies(code);
     expect(dependencies).toEqual(['a', 'b']);

packages/metro-bundler/src/JSTransformer/worker/__tests__/inline-test.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 
@@ -47,7 +49,9 @@ describe('inline constants', () => {
       var b = a.Platform.OS;
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.OS/, '"ios"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.OS/, '"ios"')),
+    );
   });
 
   it('replaces Platform.OS in the code if Platform is a top level import', () => {
@@ -58,7 +62,9 @@ describe('inline constants', () => {
         var b = a.Platform.OS;
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.OS/, '"ios"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.OS/, '"ios"')),
+    );
   });
 
   it('replaces Platform.OS in the code if Platform is a top level import from react-native', () => {
@@ -69,7 +75,9 @@ describe('inline constants', () => {
         var b = a.Platform.OS;
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.OS/, '"ios"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.OS/, '"ios"')),
+    );
   });
 
   it('replaces require("Platform").OS in the code', () => {
@@ -79,7 +87,8 @@ describe('inline constants', () => {
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/require\('Platform'\)\.OS/, '"android"')));
+      normalize(code.replace(/require\('Platform'\)\.OS/, '"android"')),
+    );
   });
 
   it('replaces React.Platform.OS in the code if React is a global', () => {
@@ -88,7 +97,9 @@ describe('inline constants', () => {
       var b = a.React.Platform.OS;
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/React\.Platform\.OS/, '"ios"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/React\.Platform\.OS/, '"ios"')),
+    );
   });
 
   it('replaces ReactNative.Platform.OS in the code if ReactNative is a global', () => {
@@ -97,7 +108,9 @@ describe('inline constants', () => {
       var b = a.ReactNative.Platform.OS;
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/ReactNative\.Platform\.OS/, '"ios"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/ReactNative\.Platform\.OS/, '"ios"')),
+    );
   });
 
   it('replaces React.Platform.OS in the code if React is a top level import', () => {
@@ -108,7 +121,9 @@ describe('inline constants', () => {
         var b = a.React.Platform.OS;
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/React.Platform\.OS/, '"ios"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/React.Platform\.OS/, '"ios"')),
+    );
   });
 
   it('replaces require("React").Platform.OS in the code', () => {
@@ -118,7 +133,8 @@ describe('inline constants', () => {
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/require\('React'\)\.Platform\.OS/, '"android"')));
+      normalize(code.replace(/require\('React'\)\.Platform\.OS/, '"android"')),
+    );
   });
 
   it('replaces ReactNative.Platform.OS in the code if ReactNative is a top level import', () => {
@@ -129,7 +145,9 @@ describe('inline constants', () => {
         var b = a.ReactNative.Platform.OS;
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/ReactNative.Platform\.OS/, '"android"')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/ReactNative.Platform\.OS/, '"android"')),
+    );
   });
 
   it('replaces require("react-native").Platform.OS in the code', () => {
@@ -139,7 +157,10 @@ describe('inline constants', () => {
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/require\('react-native'\)\.Platform\.OS/, '"android"')));
+      normalize(
+        code.replace(/require\('react-native'\)\.Platform\.OS/, '"android"'),
+      ),
+    );
   });
 
   it('inlines Platform.select in the code if Platform is a global and the argument is an object literal', () => {
@@ -148,16 +169,20 @@ describe('inline constants', () => {
       var b = a.Platform.select({ios: 1, android: 2});
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.select[^;]+/, '1')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.select[^;]+/, '1')),
+    );
   });
 
-  it('inlines Platform.select in the code if Platform is a global and the argument doesn\'t have target platform in it\'s keys', () => {
+  it("inlines Platform.select in the code if Platform is a global and the argument doesn't have target platform in it's keys", () => {
     const code = `function a() {
       var a = Platform.select({ios: 1, default: 2});
       var b = a.Platform.select({ios: 1, default: 2});
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.select[^;]+/, '2')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.select[^;]+/, '2')),
+    );
   });
 
   it('replaces Platform.select in the code if Platform is a top level import', () => {
@@ -168,7 +193,9 @@ describe('inline constants', () => {
         var b = a.Platform.select({});
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.select[^;]+/, '2')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.select[^;]+/, '2')),
+    );
   });
 
   it('replaces Platform.select in the code if Platform is a top level import from react-native', () => {
@@ -179,7 +206,9 @@ describe('inline constants', () => {
         var b = a.Platform.select({});
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.select[^;]+/, '1')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.select[^;]+/, '1')),
+    );
   });
 
   it('replaces require("Platform").select in the code', () => {
@@ -188,7 +217,9 @@ describe('inline constants', () => {
       var b = a.require('Platform').select({});
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/Platform\.select[^;]+/, '2')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/Platform\.select[^;]+/, '2')),
+    );
   });
 
   it('replaces React.Platform.select in the code if React is a global', () => {
@@ -197,7 +228,9 @@ describe('inline constants', () => {
       var b = a.React.Platform.select({});
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/React\.Platform\.select[^;]+/, '1')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/React\.Platform\.select[^;]+/, '1')),
+    );
   });
 
   it('replaces ReactNative.Platform.select in the code if ReactNative is a global', () => {
@@ -219,7 +252,9 @@ describe('inline constants', () => {
         var b = a.React.Platform.select({});
       }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'ios'});
-    expect(toString(ast)).toEqual(normalize(code.replace(/React\.Platform\.select[^;]+/, '1')));
+    expect(toString(ast)).toEqual(
+      normalize(code.replace(/React\.Platform\.select[^;]+/, '1')),
+    );
   });
 
   it('replaces require("React").Platform.select in the code', () => {
@@ -229,7 +264,8 @@ describe('inline constants', () => {
     }`;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/require\('React'\)\.Platform\.select[^;]+/, '2')));
+      normalize(code.replace(/require\('React'\)\.Platform\.select[^;]+/, '2')),
+    );
   });
 
   it('replaces ReactNative.Platform.select in the code if ReactNative is a top level import', () => {
@@ -252,14 +288,18 @@ describe('inline constants', () => {
     `;
     const {ast} = inline('arbitrary.js', {code}, {platform: 'android'});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/require\('react-native'\)\.Platform\.select[^;]+/, '2')));
+      normalize(
+        code.replace(/require\('react-native'\)\.Platform\.select[^;]+/, '2'),
+      ),
+    );
   });
 
   it('replaces non-existing properties with `undefined`', () => {
     const code = 'var a = Platform.select({ios: 1, android: 2})';
     const {ast} = inline('arbitrary.js', {code}, {platform: 'doesnotexist'});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/Platform\.select[^;]+/, 'undefined')));
+      normalize(code.replace(/Platform\.select[^;]+/, 'undefined')),
+    );
   });
 
   it('replaces process.env.NODE_ENV in the code', () => {
@@ -271,7 +311,8 @@ describe('inline constants', () => {
     }`;
     const {ast} = inline('arbitrary.js', {code}, {dev: false});
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/process\.env\.NODE_ENV/, '"production"')));
+      normalize(code.replace(/process\.env\.NODE_ENV/, '"production"')),
+    );
   });
 
   it('accepts an AST as input', function() {
@@ -286,13 +327,16 @@ describe('inline constants', () => {
       var a = Platform.OS, b = Platform.select({android: 1, ios: 2});
     });`;
     const {ast} = inline(
-      'arbitrary', {code}, {dev: true, platform: 'android', isWrapped: true});
+      'arbitrary',
+      {code},
+      {dev: true, platform: 'android', isWrapped: true},
+    );
     expect(toString(ast)).toEqual(
       normalize(
         code
           .replace(/Platform\.OS/, '"android"')
-          .replace(/Platform\.select[^)]+\)/, 1)
-      )
+          .replace(/Platform\.select[^)]+\)/, 1),
+      ),
     );
   });
 
@@ -301,9 +345,13 @@ describe('inline constants', () => {
       var a = require(arbitraryMapName[123], 'react-native').Platform.OS;
     });`;
     const {ast} = inline(
-      'arbitrary', {code}, {dev: true, platform: 'android', isWrapped: true});
+      'arbitrary',
+      {code},
+      {dev: true, platform: 'android', isWrapped: true},
+    );
     expect(toString(ast)).toEqual(
-      normalize(code.replace(/require\([^)]+\)\.Platform\.OS/, '"android"')));
+      normalize(code.replace(/require\([^)]+\)\.Platform\.OS/, '"android"')),
+    );
   });
 
   it('works with flow-declared variables', () => {
@@ -311,10 +359,10 @@ describe('inline constants', () => {
     const code = `declare var __DEV__;
       const a: boolean = __DEV__;`;
 
-    const transformed = transform(
-      code,
-      {...babelOptions, plugins: [stripFlow, [inline.plugin, {dev: false}]]},
-    ).code;
+    const transformed = transform(code, {
+      ...babelOptions,
+      plugins: [stripFlow, [inline.plugin, {dev: false}]],
+    }).code;
 
     expect(transformed).toEqual('const a=false;');
   });
@@ -326,10 +374,10 @@ describe('inline constants', () => {
       const a: boolean = __DEV__;
     });`;
 
-    const transformed = transform(
-      code,
-      {...babelOptions, plugins: [stripFlow, [inline.plugin, {dev: true}]]},
-    ).code;
+    const transformed = transform(code, {
+      ...babelOptions,
+      plugins: [stripFlow, [inline.plugin, {dev: true}]],
+    }).code;
 
     expect(transformed).toEqual('__d(()=>{const a=true;});');
   });

packages/metro-bundler/src/JSTransformer/worker/__tests__/minify-test.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 
@@ -35,11 +37,14 @@ describe('Minification:', () => {
 
   it('passes file name, code, and source map to `uglify`', () => {
     minify(filename, code, map);
-    expect(uglify.minify).toBeCalledWith(code, objectContaining({
-      fromString: true,
-      inSourceMap: map,
-      outSourceMap: true,
-    }));
+    expect(uglify.minify).toBeCalledWith(
+      code,
+      objectContaining({
+        fromString: true,
+        inSourceMap: map,
+        outSourceMap: true,
+      }),
+    );
   });
 
   it('returns the code provided by uglify', () => {

packages/metro-bundler/src/JSTransformer/worker/__tests__/worker-test.js

@@ -5,6 +5,8 @@
  * This source code is licensed under the BSD-style license found in the
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @format
  */
 'use strict';
 
@@ -22,8 +24,9 @@ describe('code transformation worker:', () => {
   beforeEach(() => {
     jest.resetModules();
     ({transformCode} = require('..'));
-    extractDependencies =
-      require('../extract-dependencies').mockReturnValue({});
+    extractDependencies = require('../extract-dependencies').mockReturnValue(
+      {},
+    );
     transformer = {
       transform: jest.fn(({filename, options, src}) => ({
         code: src,
@@ -37,7 +40,14 @@ describe('code transformation worker:', () => {
     const localPath = `local/${filename}`;
     const sourceCode = 'arbitrary(code)';
     const transformOptions = {arbitrary: 'options'};
-    transformCode(transformer, filename, localPath, sourceCode, {transform: transformOptions}, () => {});
+    transformCode(
+      transformer,
+      filename,
+      localPath,
+      sourceCode,
+      {transform: transformOptions},
+      () => {},
+    );
     expect(transformer.transform).toBeCalledWith({
       filename,
       localPath,
@@ -65,26 +75,39 @@ describe('code transformation worker:', () => {
       map: {},
     };
 
-    transformCode(transformer, 'filename', 'local/filename', result.code, {}, (error, data) => {
-      expect(error).toBeNull();
-      expect(data.result).toEqual(objectContaining(result));
-      done();
-    });
+    transformCode(
+      transformer,
+      'filename',
+      'local/filename',
+      result.code,
+      {},
+      (error, data) => {
+        expect(error).toBeNull();
+        expect(data.result).toEqual(objectContaining(result));
+        done();
+      },
+    );
   });
 
   it(
     'removes the leading assignment to `module.exports` before passing ' +
-    'on the result if the file is a JSON file, even if minified',
+      'on the result if the file is a JSON file, even if minified',
     done => {
       const code = '{a:1,b:2}';
       const filePath = 'arbitrary/file.json';
-      transformCode(transformer, filePath, filePath, code, {}, (error, data) => {
-        expect(error).toBeNull();
-        expect(data.result.code).toEqual(code);
-        done();
-      },
+      transformCode(
+        transformer,
+        filePath,
+        filePath,
+        code,
+        {},
+        (error, data) => {
+          expect(error).toBeNull();
+          expect(data.result.code).toEqual(code);
+          done();
+        },
       );
-    }
+    },
   );
 
   it('removes shebang when present', done => {
@@ -93,13 +116,20 @@ describe('code transformation worker:', () => {
       code: `${shebang} \n arbitrary(code)`,
     };
     const filePath = 'arbitrary/file.js';
-    transformCode(transformer, filePath, filePath, result.code, {}, (error, data) => {
-      expect(error).toBeNull();
-      const {code} = data.result;
-      expect(code).not.toContain(shebang);
-      expect(code.split('\n').length).toEqual(result.code.split('\n').length);
-      done();
-    });
+    transformCode(
+      transformer,
+      filePath,
+      filePath,
+      result.code,
+      {},
+      (error, data) => {
+        expect(error).toBeNull();
+        const {code} = data.result;
+        expect(code).not.toContain(shebang);
+        expect(code.split('\n').length).toEqual(result.code.split('\n').length);
+        done();
+      },
+    );
   });
 
   it('calls back with any error yielded by the transform', done => {
@@ -108,51 +138,78 @@ describe('code transformation worker:', () => {
       throw new Error(message);
     });
 
-    transformCode(transformer, 'filename', 'local/filename', 'code', {}, error => {
-      expect(error.message).toBe(message);
-      done();
-    });
+    transformCode(
+      transformer,
+      'filename',
+      'local/filename',
+      'code',
+      {},
+      error => {
+        expect(error.message).toBe(message);
+        done();
+      },
+    );
   });
 
   describe('dependency extraction', () => {
     it('passes the transformed code the `extractDependencies`', done => {
       const code = 'arbitrary(code)';
 
-      transformCode(transformer, 'filename', 'local/filename', code, {}, error => {
-        expect(error).toBeNull();
-        expect(extractDependencies).toBeCalledWith(code);
-        done();
-      });
+      transformCode(
+        transformer,
+        'filename',
+        'local/filename',
+        code,
+        {},
+        error => {
+          expect(error).toBeNull();
+          expect(extractDependencies).toBeCalledWith(code);
+          done();
+        },
+      );
     });
 
     it(
       'uses `dependencies` and `dependencyOffsets` ' +
-      'provided by `extractDependencies` for the result',
+        'provided by `extractDependencies` for the result',
       done => {
         const dependencyData = {
           dependencies: ['arbitrary', 'list', 'of', 'dependencies'],
-          dependencyOffsets: [12,  119, 185, 328, 471],
+          dependencyOffsets: [12, 119, 185, 328, 471],
         };
         extractDependencies.mockReturnValue(dependencyData);
 
-        transformCode(transformer, 'filename', 'local/filename', 'code', {}, (error, data) => {
-          expect(error).toBeNull();
-          expect(data.result).toEqual(objectContaining(dependencyData));
-          done();
-        });
-      }
+        transformCode(
+          transformer,
+          'filename',
+          'local/filename',
+          'code',
+          {},
+          (error, data) => {
+            expect(error).toBeNull();
+            expect(data.result).toEqual(objectContaining(dependencyData));
+            done();
+          },
+        );
+      },
     );
 
     it('does not extract requires of JSON files', done => {
       const jsonStr = '{"arbitrary":"json"}';
-      transformCode(transformer, 'arbitrary.json', 'local/arbitrary.json', jsonStr, {}, (error, data) => {
-        expect(error).toBeNull();
-        const {dependencies, dependencyOffsets} = data.result;
-        expect(extractDependencies).not.toBeCalled();
-        expect(dependencies).toEqual([]);
-        expect(dependencyOffsets).toEqual([]);
-        done();
-      }
+      transformCode(
+        transformer,
+        'arbitrary.json',
+        'local/arbitrary.json',
+        jsonStr,
+        {},
+        (error, data) => {
+          expect(error).toBeNull();
+          const {dependencies, dependencyOffsets} = data.result;
+          expect(extractDependencies).not.toBeCalled();
+          expect(dependencies).toEqual([]);
+          expect(dependencyOffsets).toEqual([]);
+          done();
+        },
       );
     });
   });
@@ -165,8 +222,10 @@ describe('code transformation worker:', () => {
     const foldedMap = {version: 3, sources: ['fold.js']};
 
     beforeEach(() => {
-      constantFolding = require('../constant-folding')
-        .mockReturnValue({code: foldedCode, map: foldedMap});
+      constantFolding = require('../constant-folding').mockReturnValue({
+        code: foldedCode,
+        map: foldedMap,
+      });
       extractDependencies = require('../extract-dependencies');
       inline = require('../inline');
 
@@ -177,9 +236,12 @@ describe('code transformation worker:', () => {
       };
 
       extractDependencies.mockImplementation(
-        code => code === foldedCode ? dependencyData : {});
+        code => (code === foldedCode ? dependencyData : {}),
+      );
 
-      transformer.transform.mockImplementation((src, fileName, _) => transformResult);
+      transformer.transform.mockImplementation(
+        (src, fileName, _) => transformResult,
+      );
     });
 
     it('passes the transform result to `inline` for constant inlining', done => {
@@ -207,19 +269,34 @@ describe('code transformation worker:', () => {
     });
 
     it('uses the dependencies obtained from the optimized result', done => {
-      transformCode(transformer, filename, filename, 'code', options, (_, data) => {
-        const result = data.result;
-        expect(result.dependencies).toEqual(dependencyData.dependencies);
-        done();
-      });
+      transformCode(
+        transformer,
+        filename,
+        filename,
+        'code',
+        options,
+        (_, data) => {
+          const result = data.result;
+          expect(result.dependencies).toEqual(dependencyData.dependencies);
+          done();
+        },
+      );
     });
 
     it('uses data produced by `constant-folding` for the result', done => {
-      transformCode(transformer, 'filename', 'local/filename', 'code', options, (_, data) => {
-        expect(data.result)
-          .toEqual(objectContaining({code: foldedCode, map: foldedMap}));
-        done();
-      });
+      transformCode(
+        transformer,
+        'filename',
+        'local/filename',
+        'code',
+        options,
+        (_, data) => {
+          expect(data.result).toEqual(
+            objectContaining({code: foldedCode, map: foldedMap}),
+          );
+          done();
+        },
+      );
     });
   });
 });

packages/metro-bundler/src/JSTransformer/worker/constant-folding.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';
@@ -70,11 +71,14 @@ const plugin = {
   },
 };
 
-function constantFolding(filename: string, transformResult: {
-  ast: Ast,
-  code?: ?string,
-  map: ?MappingsMap,
-}) {
+function constantFolding(
+  filename: string,
+  transformResult: {
+    ast: Ast,
+    code?: ?string,
+    map: ?MappingsMap,
+  },
+) {
   return babel.transformFromAst(transformResult.ast, transformResult.code, {
     filename,
     plugins: [plugin],

packages/metro-bundler/src/JSTransformer/worker/extract-dependencies.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';

packages/metro-bundler/src/JSTransformer/worker/index.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';
@@ -41,7 +42,6 @@ export type Transformer<ExtraOptions: {} = {}> = {
   getCacheKey: () => string,
 };
 
-
 export type TransformOptionsStrict = {|
   +dev: boolean,
   +generateSourceMaps: boolean,
@@ -73,10 +73,7 @@ export type Data = {
   transformFileEndLogEntry: LogEntry,
 };
 
-type Callback<T> = (
-  error: ?Error,
-  data: ?T,
-) => mixed;
+type Callback<T> = (error: ?Error, data: ?T) => mixed;
 
 function transformCode(
   transformer: Transformer<*>,
@@ -124,8 +121,10 @@ function transformCode(
 
   var code, map;
   if (options.minify) {
-    ({code, map} =
-      constantFolding(filename, inline(filename, transformed, options)));
+    ({code, map} = constantFolding(
+      filename,
+      inline(filename, transformed, options),
+    ));
     invariant(code != null, 'Missing code from constant-folding transform.');
   } else {
     ({code, map} = transformed);
@@ -170,7 +169,14 @@ exports.transformAndExtractDependencies = (
   babelRegisterOnly([transform]);
   /* $FlowFixMe: impossible to type a dynamic require */
   const transformModule: Transformer<*> = require(transform);
-  transformCode(transformModule, filename, localPath, sourceCode, options, callback);
+  transformCode(
+    transformModule,
+    filename,
+    localPath,
+    sourceCode,
+    options,
+    callback,
+  );
 };
 
 exports.minify = (

packages/metro-bundler/src/JSTransformer/worker/inline.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';
@@ -34,8 +35,7 @@ const importMap = new Map([['ReactNative', 'react-native']]);
 
 const isGlobal = binding => !binding;
 
-const isFlowDeclared = binding =>
-  t.isDeclareVariable(binding.path);
+const isFlowDeclared = binding => t.isDeclareVariable(binding.path);
 
 const isGlobalOrFlowDeclared = binding =>
   isGlobal(binding) || isFlowDeclared(binding);
@@ -43,7 +43,7 @@ const isGlobalOrFlowDeclared = binding =>
 const isToplevelBinding = (binding, isWrappedModule) =>
   isGlobal(binding) ||
   !binding.scope.parent ||
-  isWrappedModule && !binding.scope.parent.parent;
+  (isWrappedModule && !binding.scope.parent.parent);
 
 const isRequireCall = (node, dependencyId, scope) =>
   t.isCallExpression(node) &&
@@ -59,8 +59,8 @@ const isImport = (node, scope, patterns) =>
 function isImportOrGlobal(node, scope, patterns, isWrappedModule) {
   const identifier = patterns.find(pattern => t.isIdentifier(node, pattern));
   return (
-    identifier &&
-    isToplevelBinding(scope.getBinding(identifier.name), isWrappedModule) ||
+    (identifier &&
+      isToplevelBinding(scope.getBinding(identifier.name), isWrappedModule)) ||
     isImport(node, scope, patterns)
   );
 }
@@ -74,7 +74,11 @@ const isReactPlatformOS = (node, scope, isWrappedModule) =>
   t.isMemberExpression(node.object) &&
   t.isIdentifier(node.object.property, platform) &&
   isImportOrGlobal(
-    node.object.object, scope, [React, ReactNative], isWrappedModule);
+    node.object.object,
+    scope,
+    [React, ReactNative],
+    isWrappedModule,
+  );
 
 const isProcessEnvNodeEnv = (node, scope) =>
   t.isIdentifier(node.property, nodeEnv) &&
@@ -95,12 +99,16 @@ const isReactPlatformSelect = (node, scope, isWrappedModule) =>
   t.isMemberExpression(node.callee.object) &&
   t.isIdentifier(node.callee.object.property, platform) &&
   isImportOrGlobal(
-    node.callee.object.object, scope, [React, ReactNative], isWrappedModule);
+    node.callee.object.object,
+    scope,
+    [React, ReactNative],
+    isWrappedModule,
+  );
 
 const isDev = (node, parent, scope) =>
   t.isIdentifier(node, dev) &&
   isGlobalOrFlowDeclared(scope.getBinding(dev.name)) &&
-  !(t.isMemberExpression(parent));
+  !t.isMemberExpression(parent);
 
 function findProperty(objectExpression, key, fallback) {
   const property = objectExpression.properties.find(p => p.key.name === key);
@@ -126,7 +134,8 @@ const inlinePlugin = {
         path.replaceWith(t.stringLiteral(opts.platform));
       } else if (isProcessEnvNodeEnv(node, scope)) {
         path.replaceWith(
-          t.stringLiteral(opts.dev ? 'development' : 'production'));
+          t.stringLiteral(opts.dev ? 'development' : 'production'),
+        );
       }
     },
     CallExpression(path, state) {
@@ -155,10 +164,12 @@ const plugin = () => inlinePlugin;
 
 function checkRequireArgs(args, dependencyId) {
   const pattern = t.stringLiteral(dependencyId);
-  return t.isStringLiteral(args[0], pattern) ||
-         t.isMemberExpression(args[0]) &&
-         t.isNumericLiteral(args[0].property) &&
-         t.isStringLiteral(args[1], pattern);
+  return (
+    t.isStringLiteral(args[0], pattern) ||
+    (t.isMemberExpression(args[0]) &&
+      t.isNumericLiteral(args[0].property) &&
+      t.isStringLiteral(args[1], pattern))
+  );
 }
 
 type AstResult = {

packages/metro-bundler/src/JSTransformer/worker/minify.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @flow
+ * @format
  */
 
 'use strict';