Code Style & Performance Optimizations

.eslintrc.json

@@ -17,7 +17,9 @@
     "curly": "error",
     "eqeqeq": ["error", "always", { "null": "ignore" }],
     "no-var": "error",
+    "no-console": "error",
     "prefer-const": "error",
+    "prefer-object-spread": "error",
     "prettier/prettier": ["error"]
   }
 }

.github/actions/setup-npm-cache/action.yml

@@ -0,0 +1,14 @@
+# See https://github.com/actions/cache/blob/main/examples.md#node---npm
+name: Setup NPM cache
+runs:
+  using: composite
+  steps:
+    - id: npm-cache-dir
+      run: echo "::set-output name=dir::$(npm config get cache)"
+      shell: bash
+    - uses: actions/cache@v3
+      with:
+        path: ${{ steps.npm-cache-dir.outputs.dir }}
+        key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-node-

.github/workflows/ci.yml

@@ -0,0 +1,104 @@
+# Continuous Integration
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lint-format:
+    name: Lint & Format
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node }}
+
+      - name: Setup NPM cache
+        uses: ./.github/actions/setup-npm-cache
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Format
+        run: npm run format
+
+  test:
+    name: Test (Node.js ${{ matrix.node }} on ${{ matrix.os.name }})
+    runs-on: ${{ matrix.os.version }}
+    strategy:
+      fail-fast: false
+      matrix:
+        node:
+          - 12
+          - 14
+          - 16
+          - 17
+        os:
+          - name: Ubuntu
+            version: ubuntu-latest
+          - name: Windows
+            version: windows-latest
+          - name: macOS
+            version: macOS-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node }}
+
+      - name: Setup NPM cache
+        uses: ./.github/actions/setup-npm-cache
+
+      - name: Print versions
+        run: |
+          node --version
+          npm --version
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build
+
+      - name: Test
+        run: npm test
+        shell: bash
+        env:
+          SHELL: '/bin/bash'
+
+      - name: Submit coverage
+        uses: coverallsapp/github-action@master
+        with:
+          github-token: ${{ secrets.github_token }}
+          flag-name: Node.js ${{ matrix.node }} on ${{ matrix.os.name }}
+          parallel: true
+
+  coverage:
+    name: Coverage
+    needs: test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Finish coverage
+        uses: coverallsapp/github-action@master
+        with:
+          github-token: ${{ secrets.github_token }}
+          parallel-finished: true

README.md

@@ -85,15 +85,15 @@ package.json:
 
 ```jsonc
 {
-    //...
-    "scripts": {
-        // ...
-        "watch-js": "...",
-        "watch-css": "...",
-        "watch-node": "...",
-        // ...
-    },
+  //...
+  "scripts": {
+    // ...
+    "watch-js": "...",
+    "watch-css": "...",
+    "watch-node": "..."
     // ...
+  }
+  // ...
 }
 ```
 
@@ -115,15 +115,15 @@ Exclusion is also supported. Given the following scripts in package.json:
 
 ```jsonc
 {
+  // ...
+  "scripts": {
+    "lint:js": "...",
+    "lint:ts": "...",
+    "lint:fix:js": "...",
+    "lint:fix:ts": "..."
     // ...
-    "scripts": {
-      "lint:js": "...",
-      "lint:ts": "...",
-      "lint:fix:js": "...",
-      "lint:fix:ts": "...",
-      // ...
-    }
-    // ...
+  }
+  // ...
 }
 ```
 

bin/concurrently.spec.ts

@@ -2,11 +2,7 @@ import * as readline from 'readline';
 import _ from 'lodash';
 import * as Rx from 'rxjs';
 import { buffer, map } from 'rxjs/operators';
-import spawn from 'spawn-command';
-
-// Increasing timeout for these tests as sometimes it exceeded
-// in the CI when running on macOS / Windows (default is 5000ms)
-jest.setTimeout(10000);
+import { spawn } from 'child_process';
 
 const isWindows = process.platform === 'win32';
 const createKillMessage = (prefix: string) =>
@@ -17,14 +13,17 @@ const createKillMessage = (prefix: string) =>
  * Returns observables for its combined stdout + stderr output, close events, pid, and stdin stream.
  */
 const run = (args: string) => {
-    // TODO: This should only be transpiled once. Tests become 2.5x slower doing it in every `it`.
-    const child = spawn('ts-node --transpile-only ./concurrently.ts ' + args, {
+    // TODO: Optimally, this should only be transpiled once,
+    //       e.g. bundle in `beforeAll` and then reuse here.
+    const child = spawn(`node -r @swc-node/register ./concurrently.ts ${args}`, {
+        shell: true,
         cwd: __dirname,
-        env: Object.assign({}, process.env, {
+        env: {
+            ...process.env,
             // When upgrading from jest 23 -> 24, colors started printing in the test output.
             // They are forcibly disabled here
-            FORCE_COLOR: 0,
-        }),
+            FORCE_COLOR: '0',
+        },
     });
 
     const stdout = readline.createInterface({

bin/fixtures/read-echo.js

@@ -1,3 +1,4 @@
+/* eslint-disable no-console */
 process.stdin.on('data', chunk => {
     const line = chunk.toString().trim();
     console.log(line);

jest.config.js

@@ -0,0 +1,11 @@
+/** @type {import('@jest/types').Config.InitialOptions} */
+const config = {
+    transform: {
+        '^.+\\.(t|j)sx?$': ['@swc/jest'],
+    },
+    collectCoverage: true,
+    collectCoverageFrom: ['src/**/*.ts', '!src/index.ts'],
+    testPathIgnorePatterns: ['/node_modules/', '/dist'],
+};
+
+module.exports = config;