module-alias - npm Package Compare versions

Comparing version 2.2.3 to 2.3.0

esm-loader.mjs

+// ESM loader for module-alias
+// Provides resolve hooks for ES modules
+
+import { readFileSync, existsSync, statSync } from 'node:fs'
+import { join, resolve as pathResolve, dirname } from 'node:path'
+import { fileURLToPath, pathToFileURL } from 'node:url'
+
+let aliases = {}
+let moduleDirectories = []
+let base = process.cwd()
+let initialized = false
+
+export function init (options = {}) {
+  if (initialized) return
+
+  const thisDir = dirname(fileURLToPath(import.meta.url))
+  const candidatePaths = options.base
+    ? [pathResolve(options.base)]
+    : [join(thisDir, '../..'), process.cwd()]
+
+  let pkg
+  for (const candidate of candidatePaths) {
+    try {
+      pkg = JSON.parse(readFileSync(join(candidate, 'package.json'), 'utf8'))
+      base = candidate
+      break
+    } catch (e) {
+      // Continue to next candidate
+    }
+  }
+
+  if (!pkg) {
+    console.warn('[module-alias] Unable to find package.json in:', candidatePaths.join(', '))
+    initialized = true
+    return
+  }
+
+  // Load _moduleAliases
+  const pkgAliases = pkg._moduleAliases || {}
+  for (const alias in pkgAliases) {
+    const target = pkgAliases[alias]
+    aliases[alias] = target.startsWith('/') ? target : join(base, target)
+  }
+
+  // Load _moduleDirectories
+  if (Array.isArray(pkg._moduleDirectories)) {
+    moduleDirectories = pkg._moduleDirectories
+      .filter(d => d !== 'node_modules')
+      .map(d => join(base, d))
+  }
+
+  initialized = true
+}
+
+export function isPathMatchesAlias (path, alias) {
+  // Matching /^alias(\/|$)/
+  if (path.indexOf(alias) === 0) {
+    if (path.length === alias.length) return true
+    if (path[alias.length] === '/') return true
+  }
+  return false
+}
+
+export function resolveAlias (specifier, parentURL) {
+  init() // Ensure initialized
+
+  // Sort aliases by length (longest first) for correct matching
+  const sortedAliases = Object.keys(aliases).sort((a, b) => b.length - a.length)
+
+  for (const alias of sortedAliases) {
+    if (isPathMatchesAlias(specifier, alias)) {
+      const target = aliases[alias]
+
+      // Function-based resolver
+      if (typeof target === 'function') {
+        const parentPath = parentURL ? fileURLToPath(parentURL) : process.cwd()
+        const result = target(parentPath, specifier, alias)
+        if (!result || typeof result !== 'string') {
+          throw new Error('[module-alias] Custom handler must return path')
+        }
+        return result
+      }
+
+      // String path - join target with remainder of specifier
+      return join(target, specifier.slice(alias.length))
+    }
+  }
+
+  // Check moduleDirectories
+  for (const dir of moduleDirectories) {
+    const modulePath = join(dir, specifier)
+    // Check for directory with index.mjs/index.js
+    if (existsSync(join(modulePath, 'index.mjs'))) {
+      return join(modulePath, 'index.mjs')
+    }
+    if (existsSync(join(modulePath, 'index.js'))) {
+      return join(modulePath, 'index.js')
+    }
+    // Check for file with extension
+    if (existsSync(modulePath + '.mjs')) {
+      return modulePath + '.mjs'
+    }
+    if (existsSync(modulePath + '.js')) {
+      return modulePath + '.js'
+    }
+    // Check for exact file
+    if (existsSync(modulePath) && !statSync(modulePath).isDirectory()) {
+      return modulePath
+    }
+  }
+
+  return null
+}
+
+export function addAlias (alias, target) {
+  aliases[alias] = target
+}
+
+export function addAliases (aliasMap) {
+  for (const alias in aliasMap) {
+    addAlias(alias, aliasMap[alias])
+  }
+}
+
+export function reset () {
+  aliases = {}
+  moduleDirectories = []
+  base = process.cwd()
+  initialized = false
+}
+
+// For Node 18-21: async loader hooks
+export async function resolve (specifier, context, nextResolve) {
+  const resolved = resolveAlias(specifier, context.parentURL)
+  if (resolved) {
+    // If absolute path, convert to file URL
+    if (resolved.startsWith('/')) {
+      return { url: pathToFileURL(resolved).href, shortCircuit: true }
+    }
+    // Otherwise let Node resolve it (could be npm package)
+    return nextResolve(resolved, context)
+  }
+  return nextResolve(specifier, context)
+}
+
+export async function initialize (data) {
+  init(data || {})
+}

register.mjs

+// ESM entry point for module-alias
+// Usage: node --import module-alias/register ./app.mjs
+
+import { register } from 'node:module'
+
+// Check Node version for registerHooks support (22.15+)
+const [major, minor] = process.versions.node.split('.').map(Number)
+const hasRegisterHooks = major > 22 || (major === 22 && minor >= 15)
+
+if (hasRegisterHooks) {
+  // Node 22.15+ - use synchronous hooks on main thread
+  const { registerHooks } = await import('node:module')
+  const { resolveAlias, init } = await import('./esm-loader.mjs')
+
+  init()
+
+  registerHooks({
+    resolve (specifier, context, nextResolve) {
+      const resolved = resolveAlias(specifier, context.parentURL)
+      if (resolved) {
+        return nextResolve(resolved, context)
+      }
+      return nextResolve(specifier, context)
+    }
+  })
+} else {
+  // Node 18.19 - 22.14 - use async hooks via worker thread
+  register('./esm-loader.mjs', {
+    parentURL: import.meta.url
+  })
+}

package.json

 {
   "name": "module-alias",
   "description": "Create aliases of directories and register custom module paths",
-  "version": "2.2.3",
+  "version": "2.3.0",
   "author": {
@@ -13,2 +13,4 @@ "name": "Nick Gavrilov",
     "testonly-watch": "NODE_ENV=test mocha -w test/specs.js",
+    "test:esm": "NODE_ENV=test mocha test/esm/unit.mjs test/esm/integration.js",
+    "test:all": "npm run testonly && npm run test:esm",
     "lint": "standard"
@@ -29,5 +31,17 @@ },
   "main": "index.js",
+  "exports": {
+    ".": {
+      "require": "./index.js",
+      "import": "./index.js"
+    },
+    "./register": {
+      "require": "./register.js",
+      "import": "./register.mjs"
+    }
+  },
   "files": [
     "index.js",
     "register.js",
+    "register.mjs",
+    "esm-loader.mjs",
     "README.md",
@@ -34,0 +48,0 @@ "LICENSE"

README.md

@@ -47,2 +47,4 @@ # module-alias
 
+### CommonJS (require)
+
 Add your custom configuration to your `package.json` (in your application's root)
@@ -84,2 +86,41 @@
 
+### ES Modules (import) - Node 18+
+
+For native ES modules, use the `--import` flag:
+
+```bash
+node --import module-alias/register ./app.mjs
+```
+
+Your `package.json` configuration works the same way:
+
+```json
+{
+  "_moduleAliases": {
+    "@lib": "src/lib",
+    "@utils": "src/utils"
+  }
+}
+```
+
+Then in your ES module:
+
+```js
+import { something } from '@lib/something.js'
+```
+
+**Node Version Support:**
+
+| Node Version | API Used |
+|--------------|----------|
+| 22.15+ | `module.registerHooks()` (sync, recommended) |
+| 18.19 - 22.14 | `module.register()` (async) |
+| < 18.19 | Not supported for ESM |
+
+**ESM Limitations:**
+
+- Requires `--import` flag - cannot be imported at runtime like CJS
+- Programmatic `addAlias()` not available before app starts
+- Function-based resolvers must be configured via the loader API
+
 ## Advanced usage
@@ -86,0 +127,0 @@

New alerts

Debug access

Supply chain risk

Uses debug, reflection and dynamic code execution features.

Found 1 instance in 1 package

Dynamic require

Supply chain risk

Dynamic require can indicate the package is performing dangerous or unsafe dynamic code execution.

Found 1 instance in 1 package

Long strings

Supply chain risk

Contains long string literals, which may be a sign of obfuscated or packed code.

Found 1 instance in 1 package

Fixed alerts

Debug access

Supply chain risk

Uses debug, reflection and dynamic code execution features.

Found 1 instance in 1 package

Dynamic require

Supply chain risk

Dynamic require can indicate the package is performing dangerous or unsafe dynamic code execution.

Found 1 instance in 1 package

Long strings

Supply chain risk

Contains long string literals, which may be a sign of obfuscated or packed code.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

22616

38.36%

Number of package files

7

40%

Lines of code

339

81.28%

Number of lines in readme file

255

19.16%

No dependency changes