chore: add ESLint linting to the project (#84)

Set up ESLint with @eslint/js, @stylistic/eslint-plugin, eslint-plugin-n,
eslint-plugin-unicorn, and eslint-plugin-import-x. Add an eslint.config.js
with project-specific overrides (CJS mode, Node.js >=18, 1tbs brace style,
kebab-case filenames, prefer-const, import ordering, etc.) and a lint CI
job in the build workflow.

Apply all auto-fixable and manual lint fixes across the codebase:
- Use node: protocol for built-in requires
- Replace var/let with const where appropriate
- Add trailing commas, remove semicolons, fix spacing
- Rename files to kebab-case (test_utils.js -> test-utils.js,
  test_wasm.js -> test-wasm.js, process_discovery.js -> process-discovery.js)
- Replace .find() equality checks with .includes()
- Remove unused catch bindings
- Use top-level await where applicable
- Auto-install test subdirectory dependencies in test.sh

Author: watson

.github/actions/build-test-wasm/action.yaml

@@ -22,7 +22,7 @@ runs:
           wasm-pack build --target nodejs ./crates/${{ inputs.crate }} --out-dir ../../prebuilds/${{ inputs.crate }}
         shell: bash
       - name: Test WASM
-        run: node test_wasm.js ${{ inputs.crate }}
+        run: node test-wasm.js ${{ inputs.crate }}
         shell: bash
       - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
         with:

.github/workflows/build.yml

@@ -7,6 +7,17 @@ on:
       - main
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
+      - name: Setup Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+      - run: yarn install
+      - run: yarn install
+        working-directory: test/crashtracker
+      - run: yarn lint
+
   build-test-wasm:
     runs-on: ubuntu-latest
     strategy:

.yarnrc

@@ -0,0 +1 @@
+--ignore-engines true

eslint.config.js

@@ -0,0 +1,72 @@
+'use strict'
+
+const eslintPluginImportX = require('eslint-plugin-import-x')
+const eslintPluginJs = require('@eslint/js')
+const eslintPluginN = require('eslint-plugin-n')
+const eslintPluginStylistic = require('@stylistic/eslint-plugin')
+const eslintPluginUnicorn = require('eslint-plugin-unicorn').default
+const globals = require('globals')
+
+module.exports = [
+  eslintPluginJs.configs.recommended,
+  eslintPluginImportX.flatConfigs.recommended,
+  eslintPluginN.configs['flat/recommended-script'],
+  eslintPluginStylistic.configs.recommended,
+  eslintPluginUnicorn.configs.recommended,
+  {
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'commonjs',
+      globals: {
+        ...globals.es2022,
+        ...globals.node,
+      },
+    },
+    settings: {
+      // Used by `eslint-plugin-n` to determine the minimum version of Node.js to support.
+      // Normally setting this in the `package.json` engines field is enough, but we can't use that as it will fail
+      // when running `yarn copy-artifacts` inside the prebuildify Docker container which uses Node.js 12.
+      node: { version: '>=18.0.0' },
+    },
+    rules: {
+      '@stylistic/brace-style': ['error', '1tbs'],
+      '@stylistic/space-before-function-paren': ['error', 'always'],
+      'import-x/extensions': ['error', 'never', { json: 'always' }],
+      'import-x/no-absolute-path': 'error',
+      'import-x/no-webpack-loader-syntax': 'error',
+      'import-x/order': ['error', {
+        'newlines-between': 'always',
+      }],
+      'n/no-process-exit': 'off', // Duplicate of unicorn/no-process-exit
+      'prefer-const': 'error',
+      'unicorn/prefer-module': 'off', // We use CJS
+      'unicorn/prevent-abbreviations': 'off',
+    },
+  },
+  {
+    files: ['load.js'],
+    languageOptions: {
+      globals: {
+        __webpack_require__: 'readonly',
+        __non_webpack_require__: 'readonly',
+      },
+    },
+  },
+  {
+    // This script runs inside the prebuildify Docker container which uses Node.js 12
+    files: ['scripts/copy-artifacts.js'],
+    languageOptions: {
+      ecmaVersion: 2019,
+    },
+    settings: {
+      // Used by `eslint-plugin-n` to determine the minimum version of Node.js to support.
+      node: { version: '>=12.0.0' },
+    },
+    rules: {
+      'unicorn/prefer-node-protocol': 'off',
+    },
+  },
+  {
+    ignores: ['build/', 'target/', 'prebuilds/'],
+  },
+]

load.js

@@ -2,13 +2,13 @@
 
 // TODO: Extract this file to an external library.
 
-const { existsSync, readdirSync } = require('fs')
-const os = require('os')
-const path = require('path')
+const { existsSync, readdirSync } = require('node:fs')
+const os = require('node:os')
+const path = require('node:path')
 
 const PLATFORM = os.platform()
 const ARCH = process.arch
-const LIBC = PLATFORM === 'linux' ? existsSync('/etc/alpine-release') ? 'musl' : 'glibc' : ''
+const LIBC = PLATFORM === 'linux' ? (existsSync('/etc/alpine-release') ? 'musl' : 'glibc') : ''
 const ABI = process.versions.modules
 
 const inWebpack = typeof __webpack_require__ === 'function'
@@ -17,7 +17,7 @@ const runtimeRequire = inWebpack ? __non_webpack_require__ : require
 function maybeLoad (name) {
   try {
     return load(name)
-  } catch (e) {
+  } catch {
     // Not found, skip.
   }
 }
@@ -40,7 +40,7 @@ function findWASM (name) {
   const root = __dirname
   const prebuilds = path.join(root, 'prebuilds')
   const folders = readdirSync(prebuilds)
-  if (folders.find(f => f === name)) {
+  if (folders.includes(name)) {
     return path.join(prebuilds, name, `${name.replaceAll('-', '_')}.js`)
   }
 }
@@ -76,8 +76,8 @@ function findFolder (root) {
 
     return folders.find(f => f === `${PLATFORM}${LIBC}-${ARCH}`)
       || folders.find(f => f === `${PLATFORM}-${ARCH}`)
-  } catch (e) {
-    return null
+  } catch {
+    // Ignore
   }
 }
 

package.json

@@ -13,6 +13,7 @@
     "cargo-build-release": "yarn -s cargo-build -- --release",
     "cargo-build": "cargo build --message-format=json-render-diagnostics",
     "copy-artifacts": "node ./scripts/copy-artifacts",
+    "lint": "eslint .",
     "test": "bash scripts/test.sh"
   },
   "author": "Datadog Inc. <info@datadoghq.com>",
@@ -27,5 +28,14 @@
   "homepage": "https://github.com/DataDog/libdatadog-nodejs#readme",
   "publishConfig": {
     "access": "public"
+  },
+  "devDependencies": {
+    "@eslint/js": "^10.0.1",
+    "@stylistic/eslint-plugin": "^5.9.0",
+    "eslint": "^10.0.2",
+    "eslint-plugin-import-x": "^4.12.2",
+    "eslint-plugin-n": "^17.24.0",
+    "eslint-plugin-unicorn": "^63.0.0",
+    "globals": "^17.4.0"
   }
 }

scripts/build-wasm.js

@@ -10,42 +10,42 @@
 // Our releases are built on Linux, and fortunately no special handling is required there. This
 // script only allows development to happen on macOS.
 
-const os = require('os');
-const childProcess = require('child_process');
+const os = require('node:os')
+const childProcess = require('node:child_process')
 
-const isMacOS = os.platform() === 'darwin';
-const noWasmOpt = isMacOS ? '--no-opt' : '';
-const library = process.argv[2];
+const isMacOS = os.platform() === 'darwin'
+const noWasmOpt = isMacOS ? '--no-opt' : ''
+const library = process.argv[2]
 
 const env = {
   ...process.env,
-};
+}
 
 if (isMacOS) {
-  const homebrewDir = env.HOMEBREW_DIR ?? '/opt/homebrew';
-  const llvmDir = `${homebrewDir}/opt/llvm/`;
-  const llvmBinDir = `${llvmDir}/bin`;
+  const homebrewDir = env.HOMEBREW_DIR ?? '/opt/homebrew'
+  const llvmDir = `${homebrewDir}/opt/llvm/`
+  const llvmBinDir = `${llvmDir}/bin`
 
   try {
-    childProcess.execSync(`${llvmBinDir}/llvm-config --version`);
-  } catch (error) {
-    console.error(`‼️ LLVM not found in ${llvmDir}.\n‼️ Please install LLVM using Homebrew:\n📝   brew install llvm`);
-    process.exit(1);
+    childProcess.execSync(`${llvmBinDir}/llvm-config --version`)
+  } catch {
+    console.error(`‼️ LLVM not found in ${llvmDir}.\n‼️ Please install LLVM using Homebrew:\n📝   brew install llvm`)
+    process.exit(1) // eslint-disable-line unicorn/no-process-exit
   }
 
   if (!env.PATH.includes(llvmBinDir)) {
     // Add LLVM to PATH if not already included
-    env.PATH = `${llvmBinDir}:${env.PATH}`;
+    env.PATH = `${llvmBinDir}:${env.PATH}`
   }
 
   // Force C/C++ code (e.g. zstd-sys) to use Homebrew's clang for wasm32. Otherwise a global
   // CC (e.g. ccache cc) can point at Apple Clang, which does not support wasm32-unknown-unknown.
-  env.CC_wasm32_unknown_unknown = `${llvmBinDir}/clang`;
-  env.CXX_wasm32_unknown_unknown = `${llvmBinDir}/clang++`;
+  env.CC_wasm32_unknown_unknown = `${llvmBinDir}/clang`
+  env.CXX_wasm32_unknown_unknown = `${llvmBinDir}/clang++`
 }
 
 childProcess.execSync(
   `wasm-pack build ${noWasmOpt} --target nodejs ./crates/${library} --out-dir ../../prebuilds/${library}`, {
-    env
-  }
-);
+    env,
+  },
+)

scripts/copy-artifacts.js

@@ -10,7 +10,7 @@ const outPath = path.join(rootPath, 'target', 'out.ndjson')
 const buildPath = path.join(rootPath, 'build', 'Release')
 
 const lineReader = readline.createInterface({
-  input: fs.createReadStream(outPath)
+  input: fs.createReadStream(outPath),
 })
 
 lineReader.on('line', function (line) {

scripts/test.sh

@@ -2,6 +2,12 @@
 set -e
 
 run_test() {
+  local dir
+  dir=$(dirname "$1")
+  if [ -f "${dir}/package.json" ]; then
+    echo "Installing dependencies for $1"
+    yarn --cwd "$dir" install
+  fi
   echo "Running $1"
   node "$1"
 }

test-wasm.js

@@ -0,0 +1,10 @@
+'use strict'
+
+const fs = require('node:fs')
+
+const crateTestsDir = `./test/wasm/${process.argv[2]}`
+const files = fs.readdirSync(crateTestsDir).filter(file => file.endsWith('.js') || !file.includes('.'))
+
+for (const file of files) {
+  require(`${crateTestsDir}/${file}`)
+}