Add TypeScript extensions to EXTENSION_RE (#14)

* add compatibility with typescript when using ts-node

* add missing newline

* fix typescript tests

* run typescript tests with imhotap

* separate js tests from ts tests

* do not run test:ts with node 16.10.0

* add a FIXME comment for EXTENSION_RE changes

The addition of TS extensions to EXTENSION_RE should be temporary
until we find a better way of supporting arbitrary extensions

Co-authored-by: rochdev <roch.devost@gmail.com>

.github/workflows/ci.yml

@@ -17,3 +17,5 @@ jobs:
           node-version: ${{ matrix.node-version }}
       - run: npm install
       - run: npm test
+      - run: npm run test:ts
+        if: (matrix.node-version != '12.x' && matrix.node-version != '14.x' && matrix.node-version != '16.10.0')

hook.mjs

@@ -4,7 +4,9 @@
 
 const specifiers = new Map()
 
-const EXTENSION_RE = /\.(js|mjs|cjs)$/
+// FIXME: Typescript extensions are added temporarily until we find a better
+// way of supporting arbitrary extensions
+const EXTENSION_RE = /\.(js|mjs|cjs|ts|mts|cts)$/
 
 const NODE_MAJOR = Number(process.versions.node.split('.')[0])
 

package.json

@@ -5,6 +5,7 @@
   "main": "index.js",
   "scripts": {
     "test": "c8 --check-coverage --lines 90 imhotap --runner test/runtest --files test/{hook,low-level,other}/*",
+    "test:ts": "c8 imhotap --runner test/runtest --files test/typescript/*.test.mts",
     "coverage": "c8 --reporter html imhotap --runner test/runtest --files test/{hook,low-level,other}/* && echo '\nNow open coverage/index.html\n'"
   },
   "repository": {
@@ -26,8 +27,11 @@
   },
   "homepage": "https://github.com/DataDog/import-in-the-middle#readme",
   "devDependencies": {
+    "@types/node": "^18.0.6",
     "c8": "^7.8.0",
-    "imhotap": "^2.0.0"
+    "imhotap": "^2.0.0",
+    "ts-node": "^10.9.1",
+    "typescript": "^4.7.4"
   },
   "dependencies": {
     "module-details-from-path": "^1.0.3"

test/fixtures/say-hi.mts

@@ -0,0 +1,3 @@
+export const sayHi = (name: string) => {
+  return `Hi ${name}`
+};

test/runtest

@@ -15,7 +15,12 @@ const args = [
   ...process.argv.slice(2)
 ]
 if (!filename.includes('disabled')) {
-  args.unshift(`--experimental-loader=${path.join(__dirname, '..', 'hook.mjs')}`)
+  const isTypescript = path.extname(filename).slice(-2) === 'ts'
+  const loaderPath = isTypescript
+    ? path.join(__dirname, 'typescript', 'iitm-ts-node-loader.mjs')
+    : path.join(__dirname, '..', 'hook.mjs')
+
+  args.unshift(`--experimental-loader=${loaderPath}`)
 }
 
 spawn('node', args, { stdio: 'inherit' }).on('close', code => {

test/typescript/iitm-ts-node-loader.mjs

@@ -0,0 +1,18 @@
+import * as iitm from '../../hook.mjs'
+import * as tsNode from 'ts-node/esm.mjs'
+
+const makeNext = (loader, fnName, parentResolveOrLoad) => {
+  return (specifierOrUrl, context) => {
+    return loader[fnName](specifierOrUrl, context, parentResolveOrLoad)
+  }
+}
+
+export async function resolve(specifier, context, defaultResolve) {
+  const next = makeNext(tsNode, 'resolve', defaultResolve)
+  return iitm.resolve(specifier, context, next)
+}
+
+export async function load(url, context, defaultLoad) {
+  let next = makeNext(tsNode, 'load', defaultLoad)
+  return iitm.load(url, context, next)
+}

test/typescript/ts-node.test.mts

@@ -0,0 +1,11 @@
+import assert from 'node:assert/strict'
+import { addHook } from '../../index.js'
+import { sayHi } from '../fixtures/say-hi.mjs'
+
+addHook((url, exported) => {
+  if (url.toLowerCase().endsWith('say-hi.mts')) {
+    exported.sayHi = () => 'Hooked'
+  }
+})
+
+assert.equal(sayHi('test'), 'Hooked')

tsconfig.json

@@ -0,0 +1,14 @@
+{
+    "compilerOptions": {
+      "target": "esnext",
+      "module": "esnext",
+      "moduleResolution": "node",
+      "experimentalDecorators": true,
+      "emitDecoratorMetadata": true,
+      "allowSyntheticDefaultImports": true,
+      "noEmit": true
+    },
+    "ts-node": {
+      "esm": true
+    }
+  }