From c887959474b5e178f0305104bce6f9542872d5d4 Mon Sep 17 00:00:00 2001
From: Timo van Veenendaal <timov@microsoft.com>
Date: Thu, 21 Mar 2024 14:40:37 -0700
Subject: [PATCH] Take "target" from base tsconfig when present

---
 .tshy/build.json                                     |  1 -
 README.md                                            |  2 +-
 src/tsconfig.ts                                      | 12 ++++++++----
 tap-snapshots/test/tsconfig.ts.test.cjs              |  1 -
 test/fixtures/basic-custom-project/.tshy/build.json  |  1 -
 .../basic-imports-only-deps/.tshy/build.json         |  1 -
 test/fixtures/basic/.tshy/build.json                 |  1 -
 test/fixtures/imports-with-star/.tshy/build.json     |  1 -
 test/fixtures/imports/.tshy/build.json               |  1 -
 9 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/.tshy/build.json b/.tshy/build.json
index c51b7f5..aea1a9e 100644
--- a/.tshy/build.json
+++ b/.tshy/build.json
@@ -2,7 +2,6 @@
   "extends": "../tsconfig.json",
   "compilerOptions": {
     "rootDir": "../src",
-    "target": "es2022",
     "module": "nodenext",
     "moduleResolution": "nodenext"
   }
diff --git a/README.md b/README.md
index 870836d..178ba7e 100644
--- a/README.md
+++ b/README.md
@@ -701,7 +701,7 @@ following caveats:
   - `outDir` - will be overridden based on build, best omitted
   - `rootDir` - will be set to `./src` in the build, can only
     cause annoying errors otherwise.
-  - `target` - will be set to `es2022`
+  - `target` - will be set to `es2022` if not specified
   - `module` - will be set to `NodeNext`
   - `moduleResolution` - will be set to `NodeNext`
 
diff --git a/src/tsconfig.ts b/src/tsconfig.ts
index f3dd3d0..49d36ae 100644
--- a/src/tsconfig.ts
+++ b/src/tsconfig.ts
@@ -14,6 +14,7 @@ import * as console from './console.js'
 import config from './config.js'
 import polyfills from './polyfills.js'
 import preventVerbatimModuleSyntax from './prevent-verbatim-module-syntax.js'
+import readTypescriptConfig from './read-typescript-config.js'
 
 const {
   dialects = ['esm', 'commonjs'],
@@ -43,18 +44,21 @@ const recommended: Record<string, any> = {
   },
 }
 
-const build: Record<string, any> = {
+const build = (): Record<string, any> => ({
   extends:
     config.project === undefined
       ? '../tsconfig.json'
       : join('..', config.project),
   compilerOptions: {
+    target:
+      readTypescriptConfig().options.target === undefined
+        ? 'es2022'
+        : undefined,
     rootDir: '../src',
-    target: 'es2022',
     module: 'nodenext',
     moduleResolution: 'nodenext',
   },
-}
+})
 
 const commonjs = (dialect: string): Record<string, any> => {
   const exclude = [...relativeExclude, '../src/**/*.mts']
@@ -112,7 +116,7 @@ if (config.project === undefined && !existsSync('tsconfig.json')) {
 for (const f of readdirSync('.tshy')) {
   unlinkSync(resolve('.tshy', f))
 }
-writeConfig('build', build)
+writeConfig('build', build())
 if (dialects.includes('commonjs')) {
   writeConfig('commonjs', commonjs('cjs'))
   for (const d of commonjsDialects) {
diff --git a/tap-snapshots/test/tsconfig.ts.test.cjs b/tap-snapshots/test/tsconfig.ts.test.cjs
index bb2424f..6db2d05 100644
--- a/tap-snapshots/test/tsconfig.ts.test.cjs
+++ b/tap-snapshots/test/tsconfig.ts.test.cjs
@@ -116,7 +116,6 @@ Object {
     "module": "nodenext",
     "moduleResolution": "nodenext",
     "rootDir": "../src",
-    "target": "es2022",
   },
   "extends": "../tsconfig.json",
 }
diff --git a/test/fixtures/basic-custom-project/.tshy/build.json b/test/fixtures/basic-custom-project/.tshy/build.json
index b0321b6..1365f23 100644
--- a/test/fixtures/basic-custom-project/.tshy/build.json
+++ b/test/fixtures/basic-custom-project/.tshy/build.json
@@ -2,7 +2,6 @@
   "extends": "../tsconfig.custom.json",
   "compilerOptions": {
     "rootDir": "../src",
-    "target": "es2022",
     "module": "nodenext",
     "moduleResolution": "nodenext"
   }
diff --git a/test/fixtures/basic-imports-only-deps/.tshy/build.json b/test/fixtures/basic-imports-only-deps/.tshy/build.json
index c51b7f5..aea1a9e 100644
--- a/test/fixtures/basic-imports-only-deps/.tshy/build.json
+++ b/test/fixtures/basic-imports-only-deps/.tshy/build.json
@@ -2,7 +2,6 @@
   "extends": "../tsconfig.json",
   "compilerOptions": {
     "rootDir": "../src",
-    "target": "es2022",
     "module": "nodenext",
     "moduleResolution": "nodenext"
   }
diff --git a/test/fixtures/basic/.tshy/build.json b/test/fixtures/basic/.tshy/build.json
index c51b7f5..aea1a9e 100644
--- a/test/fixtures/basic/.tshy/build.json
+++ b/test/fixtures/basic/.tshy/build.json
@@ -2,7 +2,6 @@
   "extends": "../tsconfig.json",
   "compilerOptions": {
     "rootDir": "../src",
-    "target": "es2022",
     "module": "nodenext",
     "moduleResolution": "nodenext"
   }
diff --git a/test/fixtures/imports-with-star/.tshy/build.json b/test/fixtures/imports-with-star/.tshy/build.json
index c51b7f5..aea1a9e 100644
--- a/test/fixtures/imports-with-star/.tshy/build.json
+++ b/test/fixtures/imports-with-star/.tshy/build.json
@@ -2,7 +2,6 @@
   "extends": "../tsconfig.json",
   "compilerOptions": {
     "rootDir": "../src",
-    "target": "es2022",
     "module": "nodenext",
     "moduleResolution": "nodenext"
   }
diff --git a/test/fixtures/imports/.tshy/build.json b/test/fixtures/imports/.tshy/build.json
index c51b7f5..aea1a9e 100644
--- a/test/fixtures/imports/.tshy/build.json
+++ b/test/fixtures/imports/.tshy/build.json
@@ -2,7 +2,6 @@
   "extends": "../tsconfig.json",
   "compilerOptions": {
     "rootDir": "../src",
-    "target": "es2022",
     "module": "nodenext",
     "moduleResolution": "nodenext"
   }