From f5307f9d1390de851cfba4d57799188cd54dc418 Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Wed, 24 Nov 2021 16:02:57 +0000
Subject: [PATCH] feat(nuxi): add `typecheck` command using `vue-tsc` (#2132)

* feat(nuxi): add `typecheck` command using `vue-tsc`

* perf: use local install with execa + set rootDir as cwd
---
 docs/content/1.getting-started/5.commands.md |  8 +++++
 docs/content/2.concepts/3.typescript.md      |  4 +--
 packages/nuxi/src/commands/index.ts          |  1 +
 packages/nuxi/src/commands/typecheck.ts      | 34 ++++++++++++++++++++
 packages/schema/src/config/_internal.ts      |  2 ++
 5 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 packages/nuxi/src/commands/typecheck.ts

diff --git a/docs/content/1.getting-started/5.commands.md b/docs/content/1.getting-started/5.commands.md
index 7d27b405f5..e9c2251944 100644
--- a/docs/content/1.getting-started/5.commands.md
+++ b/docs/content/1.getting-started/5.commands.md
@@ -73,3 +73,11 @@ To upgrade Nuxt3 version:
 ```bash
 npx nuxi upgrade
 ```
+
+## Checking types
+
+To type-check your application, you can use `nuxi typecheck`. This uses [`vue-tsc`](https://github.com/johnsoncodehk/volar/tree/master/packages/vue-tsc) under the hood. If you have both a locally installed version of `typescript` and `vue-tsc`, nuxi will use these when type-checking.
+
+```bash
+npx nuxi typecheck
+```
diff --git a/docs/content/2.concepts/3.typescript.md b/docs/content/2.concepts/3.typescript.md
index 81d792089e..90551caabd 100644
--- a/docs/content/2.concepts/3.typescript.md
+++ b/docs/content/2.concepts/3.typescript.md
@@ -4,10 +4,10 @@ Nuxt 3 is fully typed and provides helpful shortcuts to ensure you have access t
 
 ## Type-checking
 
-By default, Nuxt doesn't check types when you run `nuxi dev` or `nuxi build`, for performance reasons. However, you can manually check your types using [`vue-tsc`](https://github.com/johnsoncodehk/volar/tree/master/packages/vue-tsc).
+By default, Nuxt doesn't check types when you run `nuxi dev` or `nuxi build`, for performance reasons. However, you can [manually check your types with nuxi](/getting-started/commands).
 
 ```bash
-npx vue-tsc --noEmit
+yarn nuxi typecheck
 ```
 
 ## Auto-generated types
diff --git a/packages/nuxi/src/commands/index.ts b/packages/nuxi/src/commands/index.ts
index ce99abb816..e232af1414 100644
--- a/packages/nuxi/src/commands/index.ts
+++ b/packages/nuxi/src/commands/index.ts
@@ -8,6 +8,7 @@ export const commands = {
   analyze: () => import('./analyze').then(_rDefault),
   generate: () => import('./generate').then(_rDefault),
   prepare: () => import('./prepare').then(_rDefault),
+  typecheck: () => import('./typecheck').then(_rDefault),
   usage: () => import('./usage').then(_rDefault),
   info: () => import('./info').then(_rDefault),
   init: () => import('./init').then(_rDefault),
diff --git a/packages/nuxi/src/commands/typecheck.ts b/packages/nuxi/src/commands/typecheck.ts
new file mode 100644
index 0000000000..227d0771ba
--- /dev/null
+++ b/packages/nuxi/src/commands/typecheck.ts
@@ -0,0 +1,34 @@
+import { execa } from 'execa'
+import { resolve } from 'pathe'
+import { tryResolveModule } from '../utils/cjs'
+
+import { loadKit } from '../utils/kit'
+import { writeTypes } from '../utils/prepare'
+import { defineNuxtCommand } from './index'
+
+export default defineNuxtCommand({
+  meta: {
+    name: 'typecheck',
+    usage: 'npx nuxi typecheck [rootDir]',
+    description: 'Runs `vue-tsc` to check types throughout your app.'
+  },
+  async invoke (args) {
+    process.env.NODE_ENV = process.env.NODE_ENV || 'production'
+    const rootDir = resolve(args._[0] || '.')
+
+    const { loadNuxt } = await loadKit(rootDir)
+    const nuxt = await loadNuxt({ rootDir, config: { _prepare: true } })
+
+    // Generate types and close nuxt instance
+    await writeTypes(nuxt)
+    await nuxt.close()
+
+    // Prefer local install if possible
+    const hasLocalInstall = tryResolveModule('typescript', rootDir) && tryResolveModule('vue-tsc/package.json', rootDir)
+    if (hasLocalInstall) {
+      await execa('vue-tsc', ['--noEmit'], { preferLocal: true, stdio: 'inherit', cwd: rootDir })
+    } else {
+      await execa('npx', '-p vue-tsc -p typescript vue-tsc --noEmit'.split(' '), { stdio: 'inherit', cwd: rootDir })
+    }
+  }
+})
diff --git a/packages/schema/src/config/_internal.ts b/packages/schema/src/config/_internal.ts
index 2f8a4913f5..ba3144962b 100644
--- a/packages/schema/src/config/_internal.ts
+++ b/packages/schema/src/config/_internal.ts
@@ -10,6 +10,8 @@ export default {
   /** @private */
   _generate: false,
   /** @private */
+  _prepare: false,
+  /** @private */
   _cli: false,
   /** @private */
   _requiredModules: {},