chore: migrate jest-environment-node to TypeScript (#7985)

Author: Mikael Lirbank

CHANGELOG.md

@@ -26,6 +26,7 @@
 
 ### Chore & Maintenance
 
+- `[jest-environment-node]`: Migrate to TypeScript ([#7985](https://github.com/facebook/jest/pull/7985))
 - `[*]`: Setup building, linting and testing of TypeScript ([#7808](https://github.com/facebook/jest/pull/7808), [#7855](https://github.com/facebook/jest/pull/7855), [#7951](https://github.com/facebook/jest/pull/7951))
 - `[pretty-format]`: Migrate to TypeScript ([#7809](https://github.com/facebook/jest/pull/7809), [#7809](https://github.com/facebook/jest/pull/7972))
 - `[diff-sequences]`: Migrate to Typescript ([#7820](https://github.com/facebook/jest/pull/7820))

packages/jest-config/tsconfig.json

@@ -4,9 +4,11 @@
     "rootDir": "src",
     "outDir": "build"
   },
-  // TODO: This is missing `jest-validate`, in addition to `jest-environment-jsdom`, `jest-environment-node` and
-  // `jest-jasmine2`, but those are just `require.resolve`d, so no real use for their types
+  // TODO: This is missing `jest-validate`, in addition to
+  // `jest-environment-jsdom` and `jest-jasmine2`, but those are just
+  // `require.resolve`d, so no real use for their types
   "references": [
+    {"path": "../jest-environment-node"},
     {"path": "../jest-get-type"},
     {"path": "../jest-regex-util"},
     {"path": "../jest-resolve"},

packages/jest-environment-node/package.json

@@ -8,8 +8,11 @@
   },
   "license": "MIT",
   "main": "build/index.js",
+  "types": "build/index.d.ts",
   "dependencies": {
+    "@jest/environment": "^24.1.0",
     "@jest/fake-timers": "^24.1.0",
+    "@jest/types": "^24.1.0",
     "jest-mock": "^24.0.0",
     "jest-util": "^24.0.0"
   },

packages/jest-environment-node/src/__tests__/node_environment.test.js renamed to packages/jest-environment-node/src/__tests__/node_environment.test.ts

@@ -3,33 +3,28 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
-import type {Script} from 'vm';
-import type {ProjectConfig} from 'types/Config';
-import type {Global} from 'types/Global';
-import type {ModuleMocker} from 'jest-mock';
-
-import vm from 'vm';
-import {JestFakeTimers as FakeTimers} from '@jest/fake-timers';
+import vm, {Script, Context} from 'vm';
+import {Global, Config} from '@jest/types';
+import {ModuleMocker} from 'jest-mock';
 import {installCommonGlobals} from 'jest-util';
-import mock from 'jest-mock';
+import {JestFakeTimers as FakeTimers} from '@jest/fake-timers';
+import {JestEnvironment} from '@jest/environment';
 
-type Timer = {|
-  id: number,
-  ref: () => Timer,
-  unref: () => Timer,
-|};
+type Timer = {
+  id: number;
+  ref: () => Timer;
+  unref: () => Timer;
+};
 
-class NodeEnvironment {
-  context: ?vm$Context;
-  fakeTimers: ?FakeTimers<Timer>;
-  global: ?Global;
-  moduleMocker: ?ModuleMocker;
+class NodeEnvironment implements JestEnvironment {
+  context: Context | null;
+  fakeTimers: FakeTimers<Timer> | null;
+  global: Global.Global;
+  moduleMocker: ModuleMocker | null;
 
-  constructor(config: ProjectConfig) {
+  constructor(config: Config.ProjectConfig) {
     this.context = vm.createContext();
     const global = (this.global = vm.runInContext(
       'this',
@@ -48,7 +43,7 @@ class NodeEnvironment {
       global.URLSearchParams = URLSearchParams;
     }
     installCommonGlobals(global, config.globals);
-    this.moduleMocker = new mock.ModuleMocker(global);
+    this.moduleMocker = new ModuleMocker(global);
 
     const timerIdToRef = (id: number) => ({
       id,
@@ -60,7 +55,8 @@ class NodeEnvironment {
       },
     });
 
-    const timerRefToId = (timer: Timer): ?number => (timer && timer.id) || null;
+    const timerRefToId = (timer: Timer): number | undefined =>
+      (timer && timer.id) || undefined;
 
     const timerConfig = {
       idToRef: timerIdToRef,
@@ -75,11 +71,11 @@ class NodeEnvironment {
     });
   }
 
-  setup(): Promise<void> {
+  setup() {
     return Promise.resolve();
   }
 
-  teardown(): Promise<void> {
+  teardown() {
     if (this.fakeTimers) {
       this.fakeTimers.dispose();
     }
@@ -88,13 +84,14 @@ class NodeEnvironment {
     return Promise.resolve();
   }
 
-  // Disabling rule as return type depends on script's return type.
-  runScript(script: Script): ?any {
+  // TS infers the return type to be `any`, since that's what `runInContext`
+  // returns.
+  runScript(script: Script) {
     if (this.context) {
       return script.runInContext(this.context);
     }
     return null;
   }
 }
 
-module.exports = NodeEnvironment;
+export = NodeEnvironment;

packages/jest-environment-node/src/index.js renamed to packages/jest-environment-node/src/index.ts

@@ -0,0 +1,14 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "build",
+    "rootDir": "src"
+  },
+  "references": [
+    {"path": "../jest-environment"},
+    {"path": "../jest-fake-timers"},
+    {"path": "../jest-mock"},
+    {"path": "../jest-types"},
+    {"path": "../jest-util"}
+  ]
+}

packages/jest-environment-node/tsconfig.json

@@ -4,10 +4,11 @@
     "rootDir": "src",
     "outDir": "build"
   },
-  // TODO: Missing `jest-validate` and `jest-environment-node`
+  // TODO: Missing `jest-validate`
   "references": [
     {"path": "../jest-config"},
     {"path": "../jest-environment"},
+    {"path": "../jest-environment-node"},
     {"path": "../jest-haste-map"},
     {"path": "../jest-message-util"},
     {"path": "../jest-mock"},