metro-bundler: ModuleGraph worker: @format

Reviewed By: davidaurelio

Differential Revision: D5658384

fbshipit-source-id: 918017a117e5fb574b3f6801104b4db2708a0eff

packages/metro-bundler/src/ModuleGraph/worker/JsFileWrapping.js

@@ -6,11 +6,14 @@
  * 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
  * @flow
  */
 
 'use strict';
 
+/* eslint-disable no-unclear-flowtypes */
+
 const babel = require('babel-core');
 
 const MODULE_FACTORY_PARAMETERS = ['global', 'require', 'module', 'exports'];
@@ -26,12 +29,18 @@ function wrapModule(fileAst: Object, dependencyMapName: string): Object {
 
 function wrapPolyfill(fileAst: Object): Object {
   const t = babel.types;
-  const factory = functionFromProgram(fileAst.program, POLYFILL_FACTORY_PARAMETERS);
+  const factory = functionFromProgram(
+    fileAst.program,
+    POLYFILL_FACTORY_PARAMETERS,
+  );
   const iife = t.callExpression(factory, [t.identifier('this')]);
   return t.file(t.program([t.expressionStatement(iife)]));
 }
 
-function functionFromProgram(program: Object, parameters: Array<string>): Object {
+function functionFromProgram(
+  program: Object,
+  parameters: Array<string>,
+): Object {
   const t = babel.types;
   return t.functionExpression(
     t.identifier(''),

packages/metro-bundler/src/ModuleGraph/worker/__tests__/collect-dependencies-test.js

@@ -5,7 +5,11 @@
  * 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
+ * @emails oncall+javascript_tools
  */
+
 'use strict';
 
 const collectDependencies = require('../collect-dependencies');
@@ -24,46 +28,43 @@ describe('dependency collection from ASTs:', () => {
       }
     `);
 
-    expect(collectDependencies(ast).dependencies)
+    expect(collectDependencies(ast).dependencies).toEqual([
-      .toEqual(['b/lib/a', 'do', 'setup/something']);
+      'b/lib/a',
+      'do',
+      'setup/something',
+    ]);
   });
 
   it('supports template literals as arguments', () => {
     const ast = astFromCode('require(`left-pad`)');
 
-    expect(collectDependencies(ast).dependencies)
+    expect(collectDependencies(ast).dependencies).toEqual(['left-pad']);
-      .toEqual(['left-pad']);
   });
 
   it('ignores template literals with interpolations', () => {
     const ast = astFromCode('require(`left${"-"}pad`)');
 
-    expect(collectDependencies(ast).dependencies)
+    expect(collectDependencies(ast).dependencies).toEqual([]);
-      .toEqual([]);
   });
 
   it('ignores tagged template literals', () => {
     const ast = astFromCode('require(tag`left-pad`)');
 
-    expect(collectDependencies(ast).dependencies)
+    expect(collectDependencies(ast).dependencies).toEqual([]);
-      .toEqual([]);
   });
 
   it('exposes a string as `dependencyMapName`', () => {
     const ast = astFromCode('require("arbitrary")');
-    expect(collectDependencies(ast).dependencyMapName)
+    expect(collectDependencies(ast).dependencyMapName).toEqual(any(String));
-      .toEqual(any(String));
   });
 
   it('exposes a string as `dependencyMapName` even without collecting dependencies', () => {
     const ast = astFromCode('');
-    expect(collectDependencies(ast).dependencyMapName)
+    expect(collectDependencies(ast).dependencyMapName).toEqual(any(String));
-      .toEqual(any(String));
   });
 
-  it('replaces all required module ID strings with array lookups, keeps the ID as second argument',
+  it('replaces all required module ID strings with array lookups, keeps the ID as second argument', () => {
-    () => {
+    const ast = astFromCode(`
-      const ast = astFromCode(`
         const a = require('b/lib/a');
         const b = require(123);
         exports.do = () => require("do");
@@ -72,18 +73,19 @@ describe('dependency collection from ASTs:', () => {
         }
       `);
 
-      const {dependencyMapName} = collectDependencies(ast);
+    const {dependencyMapName} = collectDependencies(ast);
 
-      expect(codeFromAst(ast)).toEqual(comparableCode(`
+    expect(codeFromAst(ast)).toEqual(
+      comparableCode(`
         const a = require(${dependencyMapName}[0], 'b/lib/a');
         const b = require(123);
         exports.do = () => require(${dependencyMapName}[1], "do");
         if (!something) {
           require(${dependencyMapName}[2], "setup/something");
         }
-      `));
+      `),
-    },
+    );
-  );
+  });
 });
 
 describe('Dependency collection from optimized ASTs:', () => {
@@ -121,13 +123,15 @@ describe('Dependency collection from optimized ASTs:', () => {
 
   it('replaces all call signatures inserted by a prior call to `collectDependencies`', () => {
     forOptimization(ast, names, dependencyMapName);
-    expect(codeFromAst(ast)).toEqual(comparableCode(`
+    expect(codeFromAst(ast)).toEqual(
+      comparableCode(`
       const a = require(${dependencyMapName}[0]);
       const b = require(123);
       exports.do = () => require(${dependencyMapName}[1]);
       if (!something) {
         require(${dependencyMapName}[2]);
       }
-    `));
+    `),
+    );
   });
 });

packages/metro-bundler/src/ModuleGraph/worker/__tests__/optimize-module-test.js

@@ -5,7 +5,11 @@
  * 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
+ * @emails oncall+javascript_tools
  */
+
 'use strict';
 
 const optimizeModule = require('../optimize-module');
@@ -23,8 +27,7 @@ describe('optimizing JS modules', () => {
     platform: 'android',
     postMinifyProcess: x => x,
   };
-  const originalCode =
+  const originalCode = `if (Platform.OS !== 'android') {
-    `if (Platform.OS !== 'android') {
       require('arbitrary-dev');
     } else {
       __DEV__ ? require('arbitrary-android-dev') : require('arbitrary-android-prod');
@@ -55,12 +58,13 @@ describe('optimizing JS modules', () => {
       const result = optimizeModule(transformResult, optimizationOptions);
       optimized = result.details.transformed.default;
       injectedVars = optimized.code.match(/function\(([^)]*)/)[1].split(',');
-      [, requireName,,, dependencyMapName] = injectedVars;
+      [, requireName, , , dependencyMapName] = injectedVars;
     });
 
     it('optimizes code', () => {
-      expect(optimized.code)
+      expect(optimized.code).toEqual(
-        .toEqual(`__d(function(${injectedVars}){${requireName}(${dependencyMapName}[0])});`);
+        `__d(function(${injectedVars}){${requireName}(${dependencyMapName}[0])});`,
+      );
     });
 
     it('extracts dependencies', () => {
@@ -72,15 +76,16 @@ describe('optimizing JS modules', () => {
       const column = optimized.code.lastIndexOf(requireName + '(');
       const loc = findLast(originalCode, 'require');
 
-      expect(consumer.originalPositionFor({line: 1, column}))
+      expect(consumer.originalPositionFor({line: 1, column})).toEqual(
-        .toEqual(objectContaining(loc));
+        objectContaining(loc),
+      );
     });
 
     it('does not extract dependencies for polyfills', () => {
-      const result = optimizeModule(
+      const result = optimizeModule(transformResult, {
-        transformResult,
+        ...optimizationOptions,
-        {...optimizationOptions, isPolyfill: true},
+        isPolyfill: true,
-      ).details;
+      }).details;
       expect(result.transformed.default.dependencies).toEqual([]);
     });
   });
@@ -90,7 +95,10 @@ describe('optimizing JS modules', () => {
     beforeEach(() => {
       postMinifyProcess = fn();
       optimize = () =>
-        optimizeModule(transformResult, {...optimizationOptions, postMinifyProcess});
+        optimizeModule(transformResult, {
+          ...optimizationOptions,
+          postMinifyProcess,
+        });
     });
 
     it('passes the result to the provided postprocessing function', () => {
@@ -104,15 +112,17 @@ describe('optimizing JS modules', () => {
       const code = 'var postprocessed = "code";';
       const map = {version: 3, mappings: 'postprocessed'};
       postMinifyProcess.stub.returns({code, map});
-      expect(optimize().details.transformed.default)
+      expect(optimize().details.transformed.default).toEqual(
-        .toEqual(objectContaining({code, map}));
+        objectContaining({code, map}),
+      );
     });
   });
 
   it('passes through non-code data unmodified', () => {
     const data = {type: 'asset', details: {arbitrary: 'data'}};
-    expect(optimizeModule(JSON.stringify(data), {dev: true, platform: ''}))
+    expect(
-      .toEqual(data);
+      optimizeModule(JSON.stringify(data), {dev: true, platform: ''}),
+    ).toEqual(data);
   });
 });
 

packages/metro-bundler/src/ModuleGraph/worker/__tests__/transform-module-test.js

@@ -7,7 +7,9 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @format
+ * @emails oncall+javascript_tools
  */
+
 'use strict';
 
 const transformModule = require('../transform-module');

packages/metro-bundler/src/ModuleGraph/worker/__tests__/wrap-worker-fn-test.js

@@ -5,12 +5,14 @@
  * 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
+ * @emails oncall+javascript_tools
  */
+
 'use strict';
 
-jest
+jest.mock('fs', () => jest.genMockFromModule('fs')).mock('mkdirp');
-  .mock('fs', () => jest.genMockFromModule('fs'))
-  .mock('mkdirp');
 
 const wrapWorkerFn = require('../wrap-worker-fn');
 const {dirname} = require('path');
@@ -63,14 +65,20 @@ describe('wrapWorkerFn:', () => {
     workerFn.stub.yields(null, result);
     wrapped(infile, outfile, {}, () => {
       expect(mkdirp.sync).toBeCalledWith(dirname(outfile));
-      expect(fs.writeFileSync).toBeCalledWith(outfile, JSON.stringify(result), 'utf8');
+      expect(fs.writeFileSync).toBeCalledWith(
+        outfile,
+        JSON.stringify(result),
+        'utf8',
+      );
       done();
     });
   });
 
   it('calls back with any error thrown by `mkdirp.sync`', done => {
     const error = new Error();
-    mkdirp.sync.mockImplementationOnce(() => { throw error; });
+    mkdirp.sync.mockImplementationOnce(() => {
+      throw error;
+    });
     wrapped(infile, outfile, {}, e => {
       expect(e).toBe(error);
       done();
@@ -79,7 +87,9 @@ describe('wrapWorkerFn:', () => {
 
   it('calls back with any error thrown by `fs.writeFileSync`', done => {
     const error = new Error();
-    fs.writeFileSync.mockImplementationOnce(() => { throw error; });
+    fs.writeFileSync.mockImplementationOnce(() => {
+      throw error;
+    });
     wrapped(infile, outfile, {}, e => {
       expect(e).toBe(error);
       done();

packages/metro-bundler/src/ModuleGraph/worker/collect-dependencies.js

@@ -6,8 +6,10 @@
  * 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
  * @flow
  */
+
 'use strict';
 
 const nullthrows = require('fbjs/lib/nullthrows');
@@ -27,8 +29,10 @@ class Replacement {
 
   isRequireCall(callee, firstArg) {
     return (
-      callee.type === 'Identifier' && callee.name === 'require' &&
+      callee.type === 'Identifier' &&
-      firstArg && isLiteralString(firstArg)
+      callee.name === 'require' &&
+      firstArg &&
+      isLiteralString(firstArg)
     );
   }
 
@@ -82,8 +86,9 @@ class ProdReplacement {
     }
 
     throw new Error(
-      `${id} is not a known module ID. Existing mappings: ${
+      `${id} is not a known module ID. Existing mappings: ${this.names
-       this.names.map((n, i) => `${i} => ${n}`).join(', ')}`
+        .map((n, i) => `${i} => ${n}`)
+        .join(', ')}`,
     );
   }
 
@@ -107,26 +112,32 @@ function createMapLookup(dependencyMapIdentifier, propertyIdentifier) {
 
 function collectDependencies(ast, replacement, dependencyMapIdentifier) {
   const traversalState = {dependencyMapIdentifier};
-  traverse(ast, {
+  traverse(
-    Program(path, state) {
+    ast,
-      if (!state.dependencyMapIdentifier) {
+    {
-        state.dependencyMapIdentifier =
+      Program(path, state) {
-          path.scope.generateUidIdentifier('dependencyMap');
+        if (!state.dependencyMapIdentifier) {
-      }
+          state.dependencyMapIdentifier = path.scope.generateUidIdentifier(
+            'dependencyMap',
+          );
+        }
+      },
+      CallExpression(path, state) {
+        const node = path.node;
+        const arg = node.arguments[0];
+        if (replacement.isRequireCall(node.callee, arg)) {
+          const index = replacement.getIndex(arg);
+          node.arguments = replacement.makeArgs(
+            types.numericLiteral(index),
+            arg,
+            state.dependencyMapIdentifier,
+          );
+        }
+      },
     },
-    CallExpression(path, state) {
+    null,
-      const node = path.node;
+    traversalState,
-      const arg = node.arguments[0];
+  );
-      if (replacement.isRequireCall(node.callee, arg)) {
-        const index = replacement.getIndex(arg);
-        node.arguments = replacement.makeArgs(
-          types.numericLiteral(index),
-          arg,
-          state.dependencyMapIdentifier,
-        );
-      }
-    },
-  }, null, traversalState);
 
   return {
     dependencies: replacement.getNames(),
@@ -135,16 +146,22 @@ function collectDependencies(ast, replacement, dependencyMapIdentifier) {
 }
 
 function isLiteralString(node) {
-  return node.type === 'StringLiteral' ||
+  return (
-         node.type === 'TemplateLiteral' && node.quasis.length === 1;
+    node.type === 'StringLiteral' ||
+    (node.type === 'TemplateLiteral' && node.quasis.length === 1)
+  );
 }
 
-exports = module.exports =
+const xp = (module.exports = (ast: AST) =>
-  (ast: AST) => collectDependencies(ast, new Replacement());
+  collectDependencies(ast, new Replacement()));
-exports.forOptimization =
+
-  (ast: AST, names: Array<string>, dependencyMapName?: string) =>
+xp.forOptimization = (
-    collectDependencies(
+  ast: AST,
-      ast,
+  names: Array<string>,
-      new ProdReplacement(names),
+  dependencyMapName?: string,
-      dependencyMapName ? types.identifier(dependencyMapName) : undefined,
+) =>
-    );
+  collectDependencies(
+    ast,
+    new ProdReplacement(names),
+    dependencyMapName ? types.identifier(dependencyMapName) : undefined,
+  );

packages/metro-bundler/src/ModuleGraph/worker/generate.js

@@ -6,21 +6,34 @@
  * 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
  * @flow
  */
+
 'use strict';
 
+/* eslint-disable no-unclear-flowtypes */
+
 const babelGenerate = require('babel-generator').default;
 
-function generate(ast: Object, filename: string, sourceCode: string, compact: boolean) {
+function generate(
-  return babelGenerate(ast, {
+  ast: Object,
-    comments: false,
+  filename: string,
-    compact,
+  sourceCode: string,
-    filename,
+  compact: boolean,
-    sourceFileName: filename,
+) {
-    sourceMaps: true,
+  return babelGenerate(
-    sourceMapTarget: filename,
+    ast,
-  }, sourceCode);
+    {
+      comments: false,
+      compact,
+      filename,
+      sourceFileName: filename,
+      sourceMaps: true,
+      sourceMapTarget: filename,
+    },
+    sourceCode,
+  );
 }
 
 module.exports = generate;

packages/metro-bundler/src/ModuleGraph/worker/optimize-module.js

@@ -6,13 +6,16 @@
  * 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
  * @flow
  */
+
 'use strict';
 
 const babel = require('babel-core');
 const collectDependencies = require('./collect-dependencies');
-const constantFolding = require('../../JSTransformer/worker/constant-folding').plugin;
+const constantFolding = require('../../JSTransformer/worker/constant-folding')
+  .plugin;
 const generate = require('./generate');
 const inline = require('../../JSTransformer/worker/inline').plugin;
 const minify = require('../../JSTransformer/worker/minify');
@@ -22,7 +25,6 @@ import type {TransformedSourceFile, TransformResult} from '../types.flow';
 import type {MappingsMap, SourceMap} from '../../lib/SourceMap';
 import type {PostMinifyProcess} from '../../Bundler/index.js';
 
-
 export type OptimizationOptions = {|
   dev: boolean,
   isPolyfill?: boolean,
@@ -46,9 +48,14 @@ function optimizeModule(
   const {postMinifyProcess} = optimizationOptions;
 
   //$FlowIssue #14545724
-  Object.entries(transformed).forEach(([k, t: TransformResult]: [*, TransformResult]) => {
+  Object.entries(
+    transformed,
+  ).forEach(([k, t: TransformResult]: [*, TransformResult]) => {
     const optimized = optimize(t, file, code, optimizationOptions);
-    const processed = postMinifyProcess({code: optimized.code, map: optimized.map});
+    const processed = postMinifyProcess({
+      code: optimized.code,
+      map: optimized.map,
+    });
     optimized.code = processed.code;
     optimized.map = processed.map;
     result.transformed[k] = optimized;
@@ -102,23 +109,22 @@ function mergeSourceMaps(
 ): MappingsMap {
   const merged = new sourceMap.SourceMapGenerator();
   const inputMap = new sourceMap.SourceMapConsumer(originalMap);
-  new sourceMap.SourceMapConsumer(secondMap)
+  new sourceMap.SourceMapConsumer(secondMap).eachMapping(mapping => {
-    .eachMapping(mapping => {
+    const original = inputMap.originalPositionFor({
-      const original = inputMap.originalPositionFor({
+      line: mapping.originalLine,
-        line: mapping.originalLine,
+      column: mapping.originalColumn,
-        column: mapping.originalColumn,
-      });
-      if (original.line == null) {
-        return;
-      }
-
-      merged.addMapping({
-        generated: {line: mapping.generatedLine, column: mapping.generatedColumn},
-        original: {line: original.line, column: original.column || 0},
-        source: file,
-        name: original.name || mapping.name,
-      });
     });
+    if (original.line == null) {
+      return;
+    }
+
+    merged.addMapping({
+      generated: {line: mapping.generatedLine, column: mapping.generatedColumn},
+      original: {line: original.line, column: original.column || 0},
+      source: file,
+      name: original.name || mapping.name,
+    });
+  });
   return merged.toJSON();
 }
 

packages/metro-bundler/src/ModuleGraph/worker/wrap-worker-fn.js

@@ -6,8 +6,10 @@
  * 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
  * @flow
  */
+
 'use strict';
 
 const fs = require('fs');