Automatically activate node source map when enabled in tsconfig.json (#…

…33)

* feat: set --enable-source-maps when sourceMap is active in tsconfig.json

* feat: enable source map when watch is active

* refactor: move source map activation in a dedicated function

* test: remove unusefull assertion in sourceMap.test.js

fixtures/ts-esm-source-map/src/add.ts

@@ -0,0 +1,4 @@
+
+export function add (x: number, y: number): number {
+  return x + y
+}

fixtures/ts-esm-source-map/test/add.test.ts

@@ -0,0 +1,7 @@
+import { test } from 'node:test'
+import { add } from '../src/add.js'
+import { strictEqual } from 'node:assert'
+
+test('add', () => {
+  strictEqual(add(1, 2), 5)
+})

fixtures/ts-esm-source-map/tsconfig.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "https://json.schemastore.org/tsconfig",
+  "compilerOptions": {
+    "outDir": "dist",
+    "sourceMap": true,
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "esModuleInterop": true,
+    "strict": true,
+    "resolveJsonModule": true,
+    "removeComments": true,
+    "newLine": "lf",
+    "noUnusedLocals": true,
+    "noFallthroughCasesInSwitch": true,
+    "isolatedModules": true,
+    "forceConsistentCasingInFileNames": true,
+    "skipLibCheck": true,
+    "lib": [
+      "ESNext"
+    ],
+    "incremental": true
+  }
+}

lib/run.js

@@ -16,6 +16,13 @@ function deferred () {
   return { resolve, reject, promise }
 }
 
+function enableSourceMapSupport (tsconfig) {
+  if (!tsconfig?.compilerOptions?.sourceMap) {
+    return
+  }
+
+  process.env.NODE_OPTIONS = (process.env.NODE_OPTIONS || '') + ' --enable-source-maps'
+}
 export default async function runWithTypeScript (config) {
   // This is a hack to override
   // https://github.com/nodejs/node/commit/d5c9adf3df
@@ -58,6 +65,8 @@ export default async function runWithTypeScript (config) {
       prefix = join(dirname(tsconfigPath), outDir)
     }
 
+    enableSourceMapSupport(tsconfig)
+
     if (tscPath) {
       // This will throw if we cannot find the `tsc` binary
       await access(tscPath)
@@ -116,6 +125,8 @@ export default async function runWithTypeScript (config) {
     if (config['post-compile'] && tsconfigPath) {
       const tsconfig = JSON.parse(await readFile(tsconfigPath))
       outDir = tsconfig.compilerOptions.outDir
+
+      enableSourceMapSupport(tsconfig)
     }
     let start = Date.now()
     tscChild = execa('node', [tscPath, ...typescriptCliArgs], { cwd })