From 31bcd044ffbd0a145d9b93515251223d9de666a8 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Mon, 22 Aug 2022 18:36:36 -0500
Subject: [PATCH] Ensure moduleResolution is written correctly (#39836)

This removes the usage of `Node12` from the `parsedValues` for `moduleResolution` as this caused false detection of `undefined` being a valid value when it was removed in TypeScript. This also copies over the test from https://github.com/vercel/next.js/pull/37302 to ensure we don't regress on this.

## Bug

- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Errors have helpful link attached, see `contributing.md`

Fixes: https://github.com/vercel/next.js/issues/37296
Closes: https://github.com/vercel/next.js/pull/37302
---
 .../typescript/writeConfigurationDefaults.ts  | 11 ++++-
 .../correct-tsconfig-defaults/index.test.ts   | 41 +++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 test/development/correct-tsconfig-defaults/index.test.ts

diff --git a/packages/next/lib/typescript/writeConfigurationDefaults.ts b/packages/next/lib/typescript/writeConfigurationDefaults.ts
index c534f63154eb..0aad82db632f 100644
--- a/packages/next/lib/typescript/writeConfigurationDefaults.ts
+++ b/packages/next/lib/typescript/writeConfigurationDefaults.ts
@@ -3,10 +3,11 @@ import chalk from 'next/dist/compiled/chalk'
 import * as CommentJson from 'next/dist/compiled/comment-json'
 import semver from 'next/dist/compiled/semver'
 import os from 'os'
+import type { CompilerOptions } from 'typescript'
 import { getTypeScriptConfiguration } from './getTypeScriptConfiguration'
 
 type DesiredCompilerOptionsShape = {
-  [key: string]:
+  [K in keyof CompilerOptions]:
     | { suggested: any }
     | {
         parsedValue?: any
@@ -58,8 +59,11 @@ function getDesiredCompilerOptions(
       parsedValues: [
         ts.ModuleResolutionKind.NodeJs,
         ts.ModuleResolutionKind.Node12,
+        // only newer TypeScript versions have this field, it
+        // will be filtered for older ones
+        (ts.ModuleResolutionKind as any).Node16,
         ts.ModuleResolutionKind.NodeNext,
-      ],
+      ].filter((val) => typeof val !== 'undefined'),
       value: 'node',
       reason: 'to match webpack resolution',
     },
@@ -86,6 +90,9 @@ export function getRequiredConfiguration(
   const desiredCompilerOptions = getDesiredCompilerOptions(ts)
   for (const optionKey of Object.keys(desiredCompilerOptions)) {
     const ev = desiredCompilerOptions[optionKey]
+    if (optionKey === 'moduleResolution') {
+      console.log({ optionKey, ev, current: res[optionKey] })
+    }
     if (!('value' in ev)) {
       continue
     }
diff --git a/test/development/correct-tsconfig-defaults/index.test.ts b/test/development/correct-tsconfig-defaults/index.test.ts
new file mode 100644
index 000000000000..c271bd9cbb89
--- /dev/null
+++ b/test/development/correct-tsconfig-defaults/index.test.ts
@@ -0,0 +1,41 @@
+import { createNext } from 'e2e-utils'
+import fs from 'fs'
+import { waitFor } from 'next-test-utils'
+import path from 'path'
+import { NextInstance } from 'test/lib/next-modes/base'
+
+describe('correct tsconfig.json defaults', () => {
+  let next: NextInstance
+
+  beforeAll(async () => {
+    next = await createNext({
+      files: {
+        'pages/index.tsx': 'export default function Page() {}',
+      },
+      skipStart: true,
+      dependencies: {
+        typescript: 'latest',
+        '@types/react': 'latest',
+        '@types/node': 'latest',
+      },
+    })
+  })
+  afterAll(() => next.destroy())
+
+  it('should add `moduleResoution` when generating tsconfig.json in dev', async () => {
+    const tsconfigPath = path.join(next.testDir, 'tsconfig.json')
+    expect(fs.existsSync(tsconfigPath)).toBeFalse()
+
+    await next.start()
+    await waitFor(1000)
+    await next.stop()
+
+    expect(fs.existsSync(tsconfigPath)).toBeTrue()
+
+    const tsconfig = JSON.parse(await next.readFile('tsconfig.json'))
+
+    expect(tsconfig.compilerOptions).toEqual(
+      expect.objectContaining({ moduleResolution: 'node' })
+    )
+  })
+})