fix: dont drop ts-node options if there are no extends

src/util/fs.ts

@@ -2,6 +2,8 @@ import {Stats, existsSync as fsExistsSync, readFileSync} from 'node:fs'
 import {readFile, stat} from 'node:fs/promises'
 import {join} from 'node:path'
 
+import {mergeNestedObjects} from './util'
+
 export function requireJson<T>(...pathParts: string[]): T {
   return JSON.parse(readFileSync(join(...pathParts), 'utf8'))
 }
@@ -73,8 +75,6 @@ export function existsSync(path: string): boolean {
 export async function readTSConfig(path: string) {
   const {parse} = await import('tsconfck')
   const result = await parse(path)
-  const tsNodeOpts = Object.fromEntries(
-    (result.extended ?? []).flatMap((e) => Object.entries(e.tsconfig['ts-node'] ?? {})).reverse(),
-  )
+  const tsNodeOpts = mergeNestedObjects(result.extended ?? [result], 'tsconfig.ts-node')
   return {...result.tsconfig, 'ts-node': tsNodeOpts}
 }

src/util/util.ts

@@ -97,3 +97,11 @@ export function mapValues<T extends Record<string, any>, TResult>(
     return o
   }, {} as any)
 }
+
+function get(obj: Record<string, any>, path: string): unknown {
+  return path.split('.').reduce((o, p) => o?.[p], obj)
+}
+
+export function mergeNestedObjects(objs: Record<string, any>[], path: string): Record<string, any> {
+  return Object.fromEntries(objs.flatMap((o) => Object.entries(get(o, path) ?? {})).reverse())
+}

test/util/util.test.ts

@@ -1,6 +1,6 @@
 import {expect} from 'chai'
 
-import {capitalize, castArray, isNotFalsy, isTruthy, last, maxBy, sumBy} from '../../src/util/util'
+import {capitalize, castArray, isNotFalsy, isTruthy, last, maxBy, mergeNestedObjects, sumBy} from '../../src/util/util'
 
 describe('capitalize', () => {
   it('capitalizes the string', () => {
@@ -96,3 +96,35 @@ describe('castArray', () => {
     expect(castArray()).to.deep.equal([])
   })
 })
+
+describe('mergeNestedObjects', () => {
+  it('should merge nested objects', () => {
+    const a = {
+      tsconfig: {
+        compilerOptions: {
+          outDir: 'dist',
+          rootDir: 'src',
+        },
+        'ts-node': {
+          transpileOnly: true,
+        },
+      },
+    }
+
+    const b = {
+      tsconfig: {
+        compilerOptions: {
+          outDir: 'dist',
+          rootDir: 'src',
+        },
+        'ts-node': {
+          transpileOnly: false,
+        },
+      },
+    }
+
+    expect(mergeNestedObjects([a, b], 'tsconfig.ts-node')).to.deep.equal({
+      transpileOnly: true,
+    })
+  })
+})