WIP: Adding an output to provide a dot file with the dependency graph

Reviewed By: davidaurelio

Differential Revision: D5284123

fbshipit-source-id: e7c7519c4fefb66245dab3c5f205a8643067693a

packages/metro-bundler/src/ModuleGraph/output/__tests__/dependencies-dot.js

@@ -0,0 +1,98 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * @flow
+ */
+'use strict';
+
+declare var jest: any;
+
+const dependenciesDot = require('../dependencies-dot');
+
+declare var describe: any;
+declare var expect: any;
+declare var it: (string, () => ?Promise<any>) => void;
+declare var beforeAll: (() => ?Promise<any>) => void;
+
+expect.extend({
+  toBeAMultilineString(received, ...args) {
+    const built = args.join('\n');
+
+    return {
+      pass: received === built,
+      message: `Expected ${received} to equal ${built}`,
+    };
+  },
+});
+
+describe('dependencies-dot', () => {
+  it('produces a valid digraph file for an empty set of modules', () => {
+    expect(dependenciesDot({modules: []})).toBeAMultilineString(
+      'digraph {',
+      '}',
+    );
+  });
+
+  it('produces an ordered file for a standard list of modules', () => {
+    expect(dependenciesDot({modules: [
+      createModule('a', ['b']),
+      createModule('b', ['c']),
+      createModule('c', []),
+    ]})).toBeAMultilineString(
+      'digraph {',
+      '\t"a" -> "b";',
+      '\t"b" -> "c";',
+      '}',
+    );
+  });
+
+  it('writes one entry per dependency', () => {
+    expect(dependenciesDot({modules: [
+      createModule('a', ['b', 'c']),
+      createModule('b', ['d']),
+      createModule('c', []),
+      createModule('d', []),
+    ]})).toBeAMultilineString(
+      'digraph {',
+      '\t"a" -> "b";',
+      '\t"a" -> "c";',
+      '\t"b" -> "d";',
+      '}',
+    );
+  });
+
+  it('handles non-printable characters', () => {
+    expect(dependenciesDot({modules: [
+      createModule('"\n', ['\r\t']),
+      createModule('\r\t', []),
+    ]})).toBeAMultilineString(
+      'digraph {',
+      '\t"\\"\\n" -> "\\r\\t";',
+      '}',
+    );
+  });
+
+  it('handles circular dependencies', () => {
+    expect(dependenciesDot({modules: [
+      createModule('a', ['b']),
+      createModule('b', ['a']),
+    ]})).toBeAMultilineString(
+      'digraph {',
+      '\t"a" -> "b";',
+      '\t"b" -> "a";',
+      '}',
+    );
+  });
+});
+
+function createModule(path: string, deps: Array<string>) {
+  return {
+    file: {code: '', map: null, path, type: 'module'},
+    dependencies: deps.map(d => ({id: d, path: d})),
+  };
+}

packages/metro-bundler/src/ModuleGraph/output/__tests__/multiple-files-ram-bundle-test.js

@@ -21,7 +21,7 @@ declare var expect: any;
 declare var it: (string, () => ?Promise<any>) => void;
 declare var beforeAll: (() => ?Promise<any>) => void;
 
-let code: Buffer;
+let code;
 let map;
 let extraFiles;
 let ids, modules, requireCall;
@@ -46,7 +46,7 @@ it('does not start the bundle file with the magic number (not a binary one)', ()
 });
 
 it('contains the startup code on the main file', () => {
-  expect(code.toString()).toBe('require(1);');
+  expect(code).toBe('require(1);');
 });
 
 it('creates a source map', () => {

packages/metro-bundler/src/ModuleGraph/output/dependencies-dot.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * @flow
+ */
+'use strict';
+
+import type {Module} from '../types.flow';
+
+function dependenciesDot({modules}: {+modules: Iterable<Module>}) {
+  const list = [];
+
+  // Opening digraph.
+  list.push('digraph {');
+
+  // Adding each module -> dependency.
+  for (const module of modules) {
+    const file = JSON.stringify(module.file.path);
+
+    module.dependencies.forEach(dependency => {
+      list.push(`\t${file} -> ${JSON.stringify(dependency.path)};`);
+    });
+  }
+
+  // Closing digraph.
+  list.push('}');
+
+  return list.join('\n');
+}
+
+module.exports = dependenciesDot;

packages/metro-bundler/src/ModuleGraph/output/multiple-files-ram-bundle.js

@@ -42,7 +42,7 @@ function asMultipleFilesRamBundle({
   deferredModules.forEach(deferredModule => {
     extraFiles.set(
       path.join(JS_MODULES, deferredModule.id + '.js'),
-      new Buffer(deferredModule.code),
+      deferredModule.code,
     );
   });