Adds linting (#51)

This'll work until eslint removes formatting support 😮‍💨

Author: jsumners-nr

.eslintrc.yaml

@@ -0,0 +1,18 @@
+overrides:
+  - files:
+    - '**/*.{js,cjs,mjs}'
+
+parser: '@babel/eslint-parser'
+parserOptions:
+  ecmaVersion: latest
+  requireConfigFile: false
+  sourceType: 'script'
+  babelOptions:
+    plugins:
+      - '@babel/plugin-syntax-import-assertions'
+
+rules:
+  "import/first": off
+
+extends:
+  - "standard"

.github/workflows/ci.yml

@@ -5,6 +5,18 @@ on:
     - cron: '0 4 * * *'
 
 jobs:
+  lint:
+    # The linting packages require modern Node.js versions in order to run.
+    # Therefore, we run linting separately and only once.
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 'lts/*'
+      - run: npm install
+      - run: npm run lint
+
   build:
     runs-on: ubuntu-latest
 

hook.js

@@ -4,7 +4,7 @@
 
 const { randomBytes } = require('crypto')
 const specifiers = new Map()
-const isWin = process.platform === "win32"
+const isWin = process.platform === 'win32'
 
 // FIXME: Typescript extensions are added temporarily until we find a better
 // way of supporting arbitrary extensions
@@ -16,7 +16,7 @@ const NODE_MINOR = Number(NODE_VERSION[1])
 let entrypoint
 
 let getExports
-if (NODE_MAJOR >= 20 || (NODE_MAJOR == 18 && NODE_MINOR >= 19)) {
+if (NODE_MAJOR >= 20 || (NODE_MAJOR === 18 && NODE_MINOR >= 19)) {
   getExports = require('./lib/get-exports.js')
 } else {
   getExports = ({ url }) => import(url).then(Object.keys)
@@ -56,7 +56,7 @@ function deleteIitm (url) {
   return resultUrl
 }
 
-function isNode16AndBiggerOrEqualsThan16_17_0() {
+function isNodeMajor16AndMinor17OrGreater () {
   return NODE_MAJOR === 16 && NODE_MINOR >= 17
 }
 
@@ -68,11 +68,11 @@ function isNodeProtocol (urlObj) {
   return urlObj.protocol === 'node:'
 }
 
-function needsToAddFileProtocol(urlObj) {
+function needsToAddFileProtocol (urlObj) {
   if (NODE_MAJOR === 17) {
     return !isFileProtocol(urlObj)
   }
-  if (isNode16AndBiggerOrEqualsThan16_17_0()) {
+  if (isNodeMajor16AndMinor17OrGreater()) {
     return !isFileProtocol(urlObj) && !isNodeProtocol(urlObj)
   }
   return !isFileProtocol(urlObj) && NODE_MAJOR < 18
@@ -87,7 +87,7 @@ function needsToAddFileProtocol(urlObj) {
  * @param {string} line
  * @returns {boolean}
  */
-function isStarExportLine(line) {
+function isStarExportLine (line) {
   return /^\* from /.test(line)
 }
 
@@ -124,7 +124,7 @@ function isStarExportLine(line) {
  *
  * @returns {Promise<ProcessedModule>}
  */
-async function processModule({
+async function processModule ({
   srcUrl,
   context,
   parentGetSource,
@@ -152,7 +152,7 @@ async function processModule({
 
   for (const n of exportNames) {
     if (isStarExportLine(n) === true) {
-      const [_, modFile] = n.split('* from ')
+      const [, modFile] = n.split('* from ')
       const normalizedModName = normalizeModName(modFile)
       const modUrl = new URL(modFile, srcUrl).toString()
       const modName = Buffer.from(modFile, 'hex') + Date.now() + randomBytes(4).toString('hex')
@@ -191,7 +191,7 @@ async function processModule({
       continue
     }
 
-    setters.set(`$${n}`+ns, `
+    setters.set(`$${n}` + ns, `
     let $${n} = ${ns}.${n}
     export { $${n} as ${n} }
     set.${n} = (v) => {
@@ -214,9 +214,9 @@ async function processModule({
  *
  * @returns {string} The normalized identifier.
  */
-function normalizeModName(name) {
+function normalizeModName (name) {
   return name
-    .split('\/')
+    .split('/')
     .pop()
     .replace(/(.+)\.(?:js|mjs)$/, '$1')
     .replaceAll(/(-.)/g, x => x[1].toUpperCase())
@@ -253,7 +253,6 @@ function createHook (meta) {
       return url
     }
 
-
     specifiers.set(url.url, specifier)
 
     return {
@@ -268,9 +267,9 @@ function createHook (meta) {
     if (hasIitm(url)) {
       const realUrl = deleteIitm(url)
       const { imports, namespaces, setters: mapSetters } = await processModule({
-          srcUrl: realUrl,
-          context,
-          parentGetSource
+        srcUrl: realUrl,
+        context,
+        parentGetSource
       })
       const setters = Array.from(mapSetters.values())
 
@@ -284,7 +283,7 @@ function createHook (meta) {
       const renamedDefaults = setters
         .map(s => {
           const matches = /let \$(.+) = (\$.+)\.default/.exec(s)
-          if (matches === null) return
+          if (matches === null) return undefined
           return `_['${matches[1]}'] = ${matches[2]}.default`
         })
         .filter(s => s)

index.js

@@ -12,26 +12,26 @@ const {
   toHook
 } = require('./lib/register')
 
-function addHook(hook) {
+function addHook (hook) {
   importHooks.push(hook)
   toHook.forEach(([name, namespace]) => hook(name, namespace))
 }
 
-function removeHook(hook) {
+function removeHook (hook) {
   const index = importHooks.indexOf(hook)
   if (index > -1) {
     importHooks.splice(index, 1)
   }
 }
 
-function callHookFn(hookFn, namespace, name, baseDir) {
+function callHookFn (hookFn, namespace, name, baseDir) {
   const newDefault = hookFn(namespace, name, baseDir)
   if (newDefault && newDefault !== namespace) {
     namespace.default = newDefault
   }
 }
 
-function Hook(modules, options, hookFn) {
+function Hook (modules, options, hookFn) {
   if ((this instanceof Hook) === false) return new Hook(modules, options, hookFn)
   if (typeof modules === 'function') {
     hookFn = modules

lib/get-esm-exports.js

@@ -1,7 +1,7 @@
 'use strict'
 
 const { Parser } = require('acorn')
-const { importAssertions } = require('acorn-import-assertions');
+const { importAssertions } = require('acorn-import-assertions')
 
 const acornOpts = {
   ecmaVersion: 'latest',

lib/get-exports.js

@@ -5,7 +5,7 @@ const { parse: getCjsExports } = require('cjs-module-lexer')
 const fs = require('fs')
 const { fileURLToPath } = require('url')
 
-function addDefault(arr) {
+function addDefault (arr) {
   return Array.from(new Set(['default', ...arr]))
 }
 

lib/register.js

@@ -2,18 +2,17 @@
 //
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2021 Datadog, Inc.
 
-
 const importHooks = [] // TODO should this be a Set?
 const setters = new WeakMap()
 const specifiers = new Map()
 const toHook = []
 
 const proxyHandler = {
-  set(target, name, value) {
+  set (target, name, value) {
     return setters.get(target)[name](value)
   },
 
-  defineProperty(target, property, descriptor) {
+  defineProperty (target, property, descriptor) {
     if ((!('value' in descriptor))) {
       throw new Error('Getters/setters are not supported for exports property descriptors.')
     }
@@ -22,7 +21,7 @@ const proxyHandler = {
   }
 }
 
-function register(name, namespace, set, specifier) {
+function register (name, namespace, set, specifier) {
   specifiers.set(name, specifier)
   setters.set(namespace, set)
   const proxy = new Proxy(namespace, proxyHandler)

package.json

@@ -6,7 +6,9 @@
   "scripts": {
     "test": "c8 --reporter lcov --check-coverage --lines 50 imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/*",
     "test:ts": "c8 --reporter lcov imhotap --runner 'node test/runtest' --files test/typescript/*.test.mts",
-    "coverage": "c8 --reporter html imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/* && echo '\nNow open coverage/index.html\n'"
+    "coverage": "c8 --reporter html imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/* && echo '\nNow open coverage/index.html\n'",
+    "lint": "eslint .",
+    "lint:fix": "eslint . --fix"
   },
   "repository": {
     "type": "git",
@@ -27,8 +29,17 @@
   },
   "homepage": "https://github.com/DataDog/import-in-the-middle#readme",
   "devDependencies": {
+    "@babel/core": "^7.23.7",
+    "@babel/eslint-parser": "^7.23.3",
+    "@babel/plugin-syntax-import-assertions": "^7.23.3",
     "@types/node": "^18.0.6",
     "c8": "^7.8.0",
+    "eslint": "^8.55.0",
+    "eslint-config-standard": "^17.1.0",
+    "eslint-plugin-import": "^2.29.0",
+    "eslint-plugin-n": "^16.4.0",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-promise": "^6.1.1",
     "imhotap": "^2.1.0",
     "ts-node": "^10.9.1",
     "typescript": "^4.7.4"

test/fixtures/a.mjs

@@ -1,6 +1,6 @@
 export const a = 'a'
 
-export function aFunc() {
+export function aFunc () {
   return a
 }
 

test/fixtures/b.mjs

@@ -1,5 +1,5 @@
 export const b = 'b'
 
-export function bFunc() {
+export function bFunc () {
   return b
 }