Convert code base to ESM import (jestjs#3778)

* Convert code base to ESM import

* [squash] specify correct babel plugin for import transpilation

* [squash] specify correct babel plugin for import transpilation in babelrc

* trigger ci

Author: SimenB

.babelrc

@@ -5,7 +5,8 @@
     "transform-es2015-destructuring",
     "transform-es2015-parameters",
     "transform-async-to-generator",
-    "transform-strict-mode"
+    "transform-strict-mode",
+    ["transform-es2015-modules-commonjs", {"allowTopLevelThis": true}]
   ],
   "retainLines": true
 }

.eslintrc.js

@@ -19,9 +19,14 @@ module.exports = {
     'flowtype/require-valid-file-annotation': 2,
     'max-len': 0,
     'no-multiple-empty-lines': 1,
-    'import/order': 2,
     'import/no-duplicates': 2,
-    'import/no-unresolved': [2, { 'ignore': ['^types/'] }]
+    'import/no-unresolved': [2, { 'ignore': ['^types/'] }],
+    // This has to be disabled until all type and module imports are combined
+    // https://github.com/benmosher/eslint-plugin-import/issues/645
+    'import/order': 0,
+    // These has to be disabled until the whole code base is converted to ESM
+    'import/default': 0,
+    'import/named': 0,
   },
   'plugins': [
     'markdown',

package.json

@@ -8,6 +8,7 @@
     "babel-plugin-syntax-trailing-function-commas": "^6.13.0",
     "babel-plugin-transform-async-to-generator": "^6.16.0",
     "babel-plugin-transform-es2015-destructuring": "^6.23.0",
+    "babel-plugin-transform-es2015-modules-commonjs": "^6.24.1",
     "babel-plugin-transform-es2015-parameters": "^6.23.0",
     "babel-plugin-transform-flow-strip-types": "^6.18.0",
     "babel-plugin-transform-runtime": "^6.23.0",

packages/babel-jest/src/index.js

@@ -11,10 +11,10 @@
 import type {Path, ProjectConfig} from 'types/Config';
 import type {TransformOptions} from 'types/Transform';
 
-const crypto = require('crypto');
-const fs = require('fs');
-const path = require('path');
-const jestPreset = require('babel-preset-jest');
+import crypto from 'crypto';
+import fs from 'fs';
+import path from 'path';
+import jestPreset from 'babel-preset-jest';
 
 const BABELRC_FILENAME = '.babelrc';
 const BABELRC_JS_FILENAME = '.babelrc.js';

packages/eslint-config-fb-strict/index.js

@@ -7,6 +7,7 @@
  *
  */
 
+// Can't be ESModules as this is not transpiled
 const fbjsConfig = require('eslint-config-fbjs');
 
 const variableNamePattern = String.raw`\s*[a-zA-Z_$][a-zA-Z_$\d]*\s*`;

packages/jest-changed-files/src/git.js

@@ -10,8 +10,8 @@
 
 import type {Path} from 'types/Config';
 
-const path = require('path');
-const childProcess = require('child_process');
+import path from 'path';
+import childProcess from 'child_process';
 
 type Options = {|
   lastCommit?: boolean,

packages/jest-changed-files/src/hg.js

@@ -10,8 +10,8 @@
 
 import type {Path} from 'types/Config';
 
-const path = require('path');
-const childProcess = require('child_process');
+import path from 'path';
+import childProcess from 'child_process';
 
 const env = Object.assign({}, process.env, {
   HGPLAIN: 1,

packages/jest-circus/src/eventHandler.js

@@ -10,7 +10,7 @@
 
 import type {EventHandler} from '../types';
 
-const {makeDescribe, getTestDuration, makeTest} = require('./utils');
+import {makeDescribe, getTestDuration, makeTest} from './utils';
 
 // To pass this value from Runtime object to state we need to use global[sym]
 const TEST_TIMEOUT_SYMBOL = Symbol.for('TEST_TIMEOUT_SYMBOL');

packages/jest-circus/src/index.js

@@ -17,7 +17,7 @@ import type {
   BlockName,
   TestName,
 } from '../types';
-const {dispatch} = require('./state');
+import {dispatch} from './state';
 
 const describe = (blockName: BlockName, blockFn: BlockFn) =>
   _dispatchDescribe(blockFn, blockName);

packages/jest-circus/src/legacy_code_todo_rewrite/jest-adapter-init.js

@@ -12,13 +12,13 @@ import type {TestResult, Status} from 'types/TestResult';
 import type {GlobalConfig, Path, ProjectConfig} from 'types/Config';
 import type {Event, TestEntry} from '../../types';
 
-const {getState, setState} = require('jest-matchers');
-const {formatResultsErrors} = require('jest-message-util');
-const {SnapshotState, addSerializer} = require('jest-snapshot');
-const {addEventHandler, ROOT_DESCRIBE_BLOCK_NAME} = require('../state');
-const {getTestID} = require('../utils');
-const run = require('../run');
-const globals = require('../index');
+import {getState, setState} from 'jest-matchers';
+import {formatResultsErrors} from 'jest-message-util';
+import {SnapshotState, addSerializer} from 'jest-snapshot';
+import {addEventHandler, ROOT_DESCRIBE_BLOCK_NAME} from '../state';
+import {getTestID} from '../utils';
+import run from '../run';
+import globals from '../index';
 
 const initialize = ({
   config,

packages/jest-circus/src/legacy_code_todo_rewrite/jest-adapter.js

@@ -14,7 +14,7 @@ import type {TestResult} from 'types/TestResult';
 import type Runtime from 'jest-runtime';
 
 const FRAMEWORK_INITIALIZER = require.resolve('./jest-adapter-init');
-const path = require('path');
+import path from 'path';
 
 const jestAdapter = async (
   globalConfig: GlobalConfig,

packages/jest-circus/src/legacy_code_todo_rewrite/jest-expect.js

@@ -10,13 +10,13 @@
 
 import type {RawMatcherFn} from 'types/Matchers';
 
-const expect = require('jest-matchers');
+import expect from 'jest-matchers';
 
-const {
+import {
   addSerializer,
   toMatchSnapshot,
   toThrowErrorMatchingSnapshot,
-} = require('jest-snapshot');
+} from 'jest-snapshot';
 
 type JasmineMatcher = {
   (): JasmineMatcher,

packages/jest-circus/src/run.js

@@ -16,13 +16,13 @@ import type {
   DescribeBlock,
 } from '../types';
 
-const {getState, dispatch} = require('./state');
-const {
+import {getState, dispatch} from './state';
+import {
   callAsyncFn,
   getAllHooksForDescribe,
   getEachHooksForTest,
   makeTestResults,
-} = require('./utils');
+} from './utils';
 
 const run = async (): Promise<TestResults> => {
   const {rootDescribeBlock} = getState();

packages/jest-circus/src/state.js

@@ -10,8 +10,8 @@
 
 import type {Event, State, EventHandler} from '../types';
 
-const {makeDescribe} = require('./utils');
-const eventHandler = require('./eventHandler');
+import {makeDescribe} from './utils';
+import eventHandler from './eventHandler';
 
 const eventHandlers: Array<EventHandler> = [eventHandler];
 

packages/jest-cli/src/PatternPrompt.js

@@ -12,9 +12,9 @@
 
 import type {ScrollOptions} from './lib/scrollList';
 
-const chalk = require('chalk');
-const ansiEscapes = require('ansi-escapes');
-const Prompt = require('./lib/Prompt');
+import chalk from 'chalk';
+import ansiEscapes from 'ansi-escapes';
+import Prompt from './lib/Prompt';
 
 const usage = (entity: string) =>
   `\n${chalk.bold('Pattern Mode Usage')}\n` +

packages/jest-cli/src/SearchSource.js

@@ -13,13 +13,11 @@ import type {Glob, Path} from 'types/Config';
 import type {ResolveModuleConfig} from 'types/Resolve';
 import type {Test} from 'types/TestRunner';
 
-const path = require('path');
-
-const micromatch = require('micromatch');
-
-const DependencyResolver = require('jest-resolve-dependencies');
-const changedFiles = require('jest-changed-files');
-const {escapePathForRegex, replacePathSepForRegex} = require('jest-regex-util');
+import path from 'path';
+import micromatch from 'micromatch';
+import DependencyResolver from 'jest-resolve-dependencies';
+import changedFiles from 'jest-changed-files';
+import {escapePathForRegex, replacePathSepForRegex} from 'jest-regex-util';
 
 type SearchResult = {|
   noSCM?: boolean,

packages/jest-cli/src/TestNamePatternPrompt.js

@@ -11,20 +11,20 @@
 import type {TestResult} from 'types/TestResult';
 import type {ScrollOptions} from './lib/scrollList';
 
-const scroll = require('./lib/scrollList');
-const {getTerminalWidth} = require('./lib/terminalUtils');
-const Prompt = require('./lib/Prompt');
-const formatTestNameByPattern = require('./lib/formatTestNameByPattern');
-const {
+import scroll from './lib/scrollList';
+import {getTerminalWidth} from './lib/terminalUtils';
+import Prompt from './lib/Prompt';
+import formatTestNameByPattern from './lib/formatTestNameByPattern';
+import {
   formatTypeaheadSelection,
   printMore,
   printPatternCaret,
   printPatternMatches,
   printRestoredPatternCaret,
   printStartTyping,
   printTypeaheadItem,
-} = require('./lib/patternModeHelpers');
-const PatternPrompt = require('./PatternPrompt');
+} from './lib/patternModeHelpers';
+import PatternPrompt from './PatternPrompt';
 
 module.exports = class TestNamePatternPrompt extends PatternPrompt {
   _cachedTestResults: Array<TestResult>;

packages/jest-cli/src/TestPathPatternPrompt.js

@@ -14,23 +14,23 @@ import type {ScrollOptions} from './lib/scrollList';
 // eslint-disable-next-line import/default
 import type SearchSource from './SearchSource';
 
-const chalk = require('chalk');
-const stringLength = require('string-length');
-const scroll = require('./lib/scrollList');
-const {getTerminalWidth} = require('./lib/terminalUtils');
-const highlight = require('./lib/highlight');
-const {trimAndFormatPath} = require('./reporters/utils');
-const Prompt = require('./lib/Prompt');
-const {
+import chalk from 'chalk';
+import stringLength from 'string-length';
+import scroll from './lib/scrollList';
+import {getTerminalWidth} from './lib/terminalUtils';
+import highlight from './lib/highlight';
+import {trimAndFormatPath} from './reporters/utils';
+import Prompt from './lib/Prompt';
+import {
   formatTypeaheadSelection,
   printMore,
   printPatternCaret,
   printPatternMatches,
   printRestoredPatternCaret,
   printStartTyping,
   printTypeaheadItem,
-} = require('./lib/patternModeHelpers');
-const PatternPrompt = require('./PatternPrompt');
+} from './lib/patternModeHelpers';
+import PatternPrompt from './PatternPrompt';
 
 type SearchSources = Array<{|
   context: Context,

packages/jest-cli/src/TestRunner.js

@@ -18,19 +18,18 @@ import type {Context} from 'types/Context';
 import type {Reporter, Test} from 'types/TestRunner';
 import type {PathPattern} from './SearchSource';
 
-const {formatExecError} = require('jest-message-util');
-const snapshot = require('jest-snapshot');
-const pify = require('pify');
-const throat = require('throat');
-const workerFarm = require('worker-farm');
-
-const DefaultReporter = require('./reporters/DefaultReporter');
-const NotifyReporter = require('./reporters/NotifyReporter');
-const SummaryReporter = require('./reporters/SummaryReporter');
-const VerboseReporter = require('./reporters/VerboseReporter');
-const runTest = require('./runTest');
-const TestWatcher = require('./TestWatcher');
-const ReporterDispatcher = require('./ReporterDispatcher');
+import {formatExecError} from 'jest-message-util';
+import snapshot from 'jest-snapshot';
+import pify from 'pify';
+import throat from 'throat';
+import workerFarm from 'worker-farm';
+import DefaultReporter from './reporters/DefaultReporter';
+import NotifyReporter from './reporters/NotifyReporter';
+import SummaryReporter from './reporters/SummaryReporter';
+import VerboseReporter from './reporters/VerboseReporter';
+import runTest from './runTest';
+import TestWatcher from './TestWatcher';
+import ReporterDispatcher from './ReporterDispatcher';
 
 const SLOW_TEST_TIME = 3000;
 

packages/jest-cli/src/TestSequencer.js

@@ -12,8 +12,9 @@ import type {AggregatedResult} from 'types/TestResult';
 import type {Context} from 'types/Context';
 import type {Test} from 'types/TestRunner';
 
-const fs = require('fs');
-const getCacheFilePath = require('jest-haste-map').getCacheFilePath;
+import fs from 'fs';
+// $FlowFixMe: Missing ESM export
+import {getCacheFilePath} from 'jest-haste-map';
 
 const FAIL = 0;
 const SUCCESS = 1;

packages/jest-cli/src/TestWatcher.js

@@ -8,7 +8,7 @@
  * @flow
  */
 
-const {EventEmitter} = require('events');
+import EventEmitter from 'events';
 
 type State = {|
   interrupted: boolean,

packages/jest-cli/src/TestWorker.js

@@ -18,11 +18,11 @@ process.on('uncaughtException', err => {
   process.exit(1);
 });
 
-const {ModuleMap} = require('jest-haste-map');
-const {separateMessageFromStack} = require('jest-message-util');
-
-const Runtime = require('jest-runtime');
-const runTest = require('./runTest');
+// $FlowFixMe: Missing ESM export
+import {ModuleMap} from 'jest-haste-map';
+import {separateMessageFromStack} from 'jest-message-util';
+import Runtime from 'jest-runtime';
+import runTest from './runTest';
 
 type WorkerData = {|
   config: ProjectConfig,
@@ -59,6 +59,7 @@ const getResolver = (config, rawModuleMap) => {
   if (rawModuleMap) {
     return Runtime.createResolver(
       config,
+      // $FlowFixMe: Missing ESM export
       new ModuleMap(rawModuleMap.map, rawModuleMap.mocks),
     );
   } else {

packages/jest-cli/src/cli/args.js

@@ -10,7 +10,7 @@
 
 import type {Argv} from 'types/Argv';
 
-const isCI = require('is-ci');
+import isCI from 'is-ci';
 
 const check = (argv: Argv) => {
   if (argv.runInBand && argv.hasOwnProperty('maxWorkers')) {

packages/jest-cli/src/cli/getJest.js

@@ -10,9 +10,9 @@
 
 import type {Path} from 'types/Config';
 
-const path = require('path');
-const chalk = require('chalk');
-const fs = require('graceful-fs');
+import path from 'path';
+import chalk from 'chalk';
+import fs from 'graceful-fs';
 
 function getJest(packageRoot: Path) {
   const packageJSONPath = path.join(packageRoot, 'package.json');

packages/jest-cli/src/cli/index.js

@@ -11,11 +11,11 @@
 import type {Path} from 'types/Config';
 import type {Argv} from 'types/Argv';
 
-const {validateCLIOptions} = require('jest-util');
-const yargs = require('yargs');
-const args = require('./args');
-const getJest = require('./getJest');
-const runCLI = require('./runCLI');
+import {validateCLIOptions} from 'jest-util';
+import yargs from 'yargs';
+import args from './args';
+import getJest from './getJest';
+import runCLI from './runCLI';
 
 function run(argv?: Argv, project?: Path) {
   argv = yargs(argv || process.argv.slice(2))