Audit @flow and "use strict" (jestjs#3451)

* Remove 'use strict' from all files

* 'use strict' removed from pacakges' sources
* Strict mode is now enabled automatically by babel
* 'use strict' check removed from dangerfile
* Updated contributing guidelines

* Enable @flow for most files

* Commit yarn.lock

* Revert removal of "use strict" in test and mock files

* Improve annotations for ReportDispatcher

* Replace "void 0" with "undefined"

* Update babel-plugin-transform-strict-mode to match transitive deps

.babelrc

@@ -4,7 +4,8 @@
     "transform-flow-strip-types",
     "transform-es2015-destructuring",
     "transform-es2015-parameters",
-    "transform-async-to-generator"
+    "transform-async-to-generator",
+    "transform-strict-mode"
   ],
   "retainLines": true
 }

CONTRIBUTING.md

@@ -154,7 +154,6 @@ Facebook has a [bounty program](https://www.facebook.com/whitehat/) for the safe
 * 80 character line length strongly preferred.
 * Prefer `'` over `"`.
 * ES6 syntax when possible.
-* `'use strict';`.
 * Use [Flow types](http://flowtype.org/).
 * Use semicolons;
 * Trailing commas,

dangerfile.js

@@ -10,8 +10,6 @@
 
 // Want to make changes? Check out the README in /danger/README.md for advice
 
-'use strict';
-
 const fs = require('fs');
 const {danger, fail, warn} = require('danger');
 // As danger's deps are inside a sub-folder, need to resolve via relative paths
@@ -88,18 +86,6 @@ const noFlowFiles = newJsFiles.filter(isSourceFile).filter(filepath => {
 
 raiseIssueAboutPaths(warn, noFlowFiles, '@flow');
 
-// detects the presence of ES module import/export syntax, while ignoring the
-// variant introduced by flowtype; examples here: http://regexr.com/3f64p
-const esModuleRegex = /^(import|export)\s(?!type(of\s|\s)(?!from)).*?$/gm;
-
-// Ensure the use of 'use strict' on all non-ES module files
-const noStrictFiles = newJsFiles.filter(filepath => {
-  const content = fs.readFileSync(filepath, 'utf8');
-  return !content.match(esModuleRegex) && !includes(content, 'use strict');
-});
-
-raiseIssueAboutPaths(fail, noStrictFiles, "'use strict'");
-
 // No merge from master commmits
 // TODO: blocked by https://github.com/danger/danger-js/issues/81
 

examples/async/request.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 const http = require('http');
 
 export default function request(url) {

examples/async/user.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 import request from './request';
 
 export function getUserName(userID) {

examples/getting_started/sum.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 function sum(a, b) {
   return a + b;
 }

examples/getting_started/sum.test.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 test('adds 1 + 2 to equal 3', () => {
   const sum = require('./sum');
   expect(sum(1, 2)).toBe(3);

examples/jquery/fetchCurrentUser.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 const $ = require('jquery');
 
 function parseJSON(user) {

examples/manual_mocks/FileSummarizer.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 const fs = require('fs');
 
 function summarizeFilesInDirectorySync(directory) {

examples/react-native/Intro.js

@@ -3,7 +3,6 @@
  * https://github.com/facebook/react-native
  * @flow
  */
-'use strict';
 
 import React, {Component} from 'react';
 import {StyleSheet, Text, View} from 'react-native';

examples/timer/infiniteTimerGame.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 function infiniteTimerGame(callback) {
   console.log('Ready....go!');
 

examples/timer/timerGame.js

@@ -1,7 +1,5 @@
 // Copyright 2004-present Facebook. All Rights Reserved.
 
-'use strict';
-
 function timerGame(callback) {
   console.log('Ready....go!');
   setTimeout(() => {

fixtures/parserTests.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const fixtures = __dirname;
 
 function parserTests(parse: (file: string) => any) {

flow-typed/console.js

@@ -7,7 +7,6 @@
  *
  * @flow
  */
-'use strict';
 
 declare module "console" {
   declare export class Console {

flow-typed/graceful-fs.js

@@ -7,7 +7,6 @@
  *
  * @flow
  */
-'use strict';
 
 declare module "graceful-fs" {
   declare class Stats {

flow-typed/resolve.js

@@ -7,7 +7,6 @@
  *
  * @flow
  */
-'use strict';
 
 declare module "resolve" {
   declare function isCore(moduleName: string): boolean;

integration_tests/__tests__/__snapshots__/coverage_report-test.js.snap

@@ -15,7 +15,7 @@ exports[`collects coverage only from specified files avoiding dependencies 1`] =
 File      |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
 ----------|----------|----------|----------|----------|----------------|
 All files |    85.71 |      100 |       50 |    85.71 |                |
- sum.js   |    85.71 |      100 |       50 |    85.71 |             14 |
+ sum.js   |    85.71 |      100 |       50 |    85.71 |             13 |
 ----------|----------|----------|----------|----------|----------------|
 "
 `;
@@ -34,10 +34,10 @@ exports[`outputs coverage report 1`] = `
 File                           |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
 -------------------------------|----------|----------|----------|----------|----------------|
 All files                      |    41.18 |        0 |       25 |    41.18 |                |
- not-required-in-test-suite.js |        0 |        0 |        0 |        0 | 10,17,18,19,21 |
+ not-required-in-test-suite.js |        0 |        0 |        0 |        0 |  9,16,17,18,20 |
  other-file.js                 |      100 |      100 |      100 |      100 |                |
- sum.js                        |    85.71 |      100 |       50 |    85.71 |             14 |
- sum_dependency.js             |        0 |        0 |        0 |        0 |    10,12,13,16 |
+ sum.js                        |    85.71 |      100 |       50 |    85.71 |             13 |
+ sum_dependency.js             |        0 |        0 |        0 |        0 |     9,11,12,15 |
 -------------------------------|----------|----------|----------|----------|----------------|
 "
 `;

integration_tests/__tests__/__snapshots__/transform-test.js.snap

@@ -5,7 +5,7 @@ exports[`babel-jest instruments only specific files and collects coverage 1`] =
 File        |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
 ------------|----------|----------|----------|----------|----------------|
 All files   |    83.33 |      100 |       50 |    83.33 |                |
- covered.js |    83.33 |      100 |       50 |    83.33 |             18 |
+ covered.js |    83.33 |      100 |       50 |    83.33 |             16 |
 ------------|----------|----------|----------|----------|----------------|
 "
 `;
@@ -24,7 +24,7 @@ exports[`no babel-jest instrumentation with no babel-jest 1`] = `
 File        |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
 ------------|----------|----------|----------|----------|----------------|
 All files   |    83.33 |      100 |       50 |    83.33 |                |
- covered.js |    83.33 |      100 |       50 |    83.33 |             18 |
+ covered.js |    83.33 |      100 |       50 |    83.33 |             16 |
 ------------|----------|----------|----------|----------|----------------|
 "
 `;

integration_tests/__tests__/debug-test.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const path = require('path');
 const skipOnWindows = require('skipOnWindows');
 const {linkJestPackage} = require('../utils');

integration_tests/__tests__/failures-test.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const path = require('path');
 const skipOnWindows = require('skipOnWindows');
 const {extractSummary} = require('../utils');

integration_tests/__tests__/toMatchSnapshot-test.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const path = require('path');
 const {makeTemplate, writeFiles, cleanup} = require('../utils');
 const runJest = require('../runJest');

integration_tests/__tests__/toThrowErrorMatchingSnapshot-test.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const path = require('path');
 const {makeTemplate, writeFiles, cleanup} = require('../utils');
 const runJest = require('../runJest');

integration_tests/__tests__/transform-test.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const path = require('path');
 const skipOnWindows = require('skipOnWindows');
 const {linkJestPackage, run} = require('../utils');

integration_tests/__tests__/typescript-coverage-test.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const path = require('path');
 const skipOnWindows = require('skipOnWindows');
 const {run} = require('../utils');

integration_tests/auto-clear-mocks/with-auto-clear/index.js

@@ -8,6 +8,4 @@
  * @flow
  */
 
-'use strict';
-
 module.exports = () => {};

integration_tests/auto-clear-mocks/without-auto-clear/index.js

@@ -8,6 +8,4 @@
  * @flow
  */
 
-'use strict';
-
 module.exports = () => {};

integration_tests/auto-reset-mocks/with-auto-reset/index.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 module.exports = () => {};

integration_tests/auto-reset-mocks/without-auto-reset/index.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 module.exports = () => {};

integration_tests/babel-plugin-jest-hoist/__test_modules__/Mocked.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default class Mocked {
   constructor() {
     this.isMocked = true;

integration_tests/babel-plugin-jest-hoist/__test_modules__/Unmocked.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default class Unmocked {
   constructor() {
     this.isUnmocked = true;

integration_tests/babel-plugin-jest-hoist/__test_modules__/a.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default () => 'unmocked';

integration_tests/babel-plugin-jest-hoist/__test_modules__/b.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default () => 'unmocked';

integration_tests/babel-plugin-jest-hoist/__test_modules__/c.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default () => 'unmocked';

integration_tests/babel-plugin-jest-hoist/__test_modules__/d.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default () => 'unmocked';

integration_tests/babel-plugin-jest-hoist/__test_modules__/e.js

@@ -6,6 +6,4 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 export default () => 'unmocked';

integration_tests/coverage-remapping/typescript-preprocessor.js

@@ -6,8 +6,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-'use strict';
-
 const tsc = require('typescript');
 
 module.exports = {

integration_tests/coverage_report/not-required-in-test-suite.js

@@ -5,7 +5,6 @@
  * 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.
  */
-'use strict';
 
 throw new Error(
   `this error should not be a problem because` +

integration_tests/coverage_report/other-file.js

@@ -5,6 +5,5 @@
  * 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.
  */
-'use strict';
 
 module.exports = {a: 5};

integration_tests/coverage_report/setup.js

@@ -5,6 +5,5 @@
  * 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.
  */
-'use strict';
 
 global.setup = true;

integration_tests/coverage_report/sum.js

@@ -5,7 +5,6 @@
  * 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.
  */
-'use strict';
 
 require('./sum_dependency.js');
 require('./other-file');

integration_tests/coverage_report/sum_dependency.js

@@ -5,7 +5,6 @@
  * 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.
  */
-'use strict';
 
 require('path');
 

integration_tests/json_reporter/sum.js

@@ -5,7 +5,6 @@
  * 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.
  */
-'use strict';
 
 module.exports = function(a, b) {
   return a + b;

integration_tests/resolve/test1.android.js

@@ -5,6 +5,5 @@
  * 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.
  */
-'use strict';
 
 module.exports = {extension: 'android.js'};

integration_tests/resolve/test1.js

@@ -5,6 +5,5 @@
  * 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.
  */
-'use strict';
 
 module.exports = {extension: 'js'};