Add support for TypeScript 7

[abhishekmardiya]

After upgrading typescript from 6.x to 7.0.2 (the new native Go port announced in Announcing TypeScript 7.0), Next.js no longer detects TypeScript and aborts on next build with:

It looks like you're trying to use TypeScript but do not have the required package(s) installed.
Installing dependencies

If you are not trying to use TypeScript, please remove the tsconfig.json file from your package root
(and any TypeScript files in your app and pages directories).

Root cause

Root cause identified with the help of Claude (Claude Code).

The TypeScript 7.0 typescript npm package ships the Go-based compiler and no longer includes lib/typescript.js (the JavaScript Compiler API). The lib/ directory now only contains a tsc.js shim that delegates to a native binary (@typescript/typescript-<platform>-<arch>):

$ ls node_modules/typescript/lib/typescript.js
ls: node_modules/typescript/lib/typescript.js: No such file or directory

$ ls node_modules/@typescript/
typescript-darwin-arm64

Next.js's TypeScript integration resolves and loads TypeScript as a JS module (the Compiler API — createProgram, the TS language-service plugin, next.config.ts type support). Because the JS API is gone in the 7.0 package layout, that detection fails and Next reports the package as missing/not installed even though typescript@7.0.2 is installed and npx tsc --version works.

Reproduction

1. Any Next.js 16 app with a tsconfig.json.
2. npm install -D typescript@7 (installs 7.0.2, the native port).
3. npm run dev (or next build).
4. Observe the "required package(s) are not installed" error.

Reverting to typescript@^6 restores lib/typescript.js and everything works again (next dev/build and tsc --noEmit all pass).

Expected behavior

Next.js should either:

1. Support loading TypeScript via the 7.0 native port (however the API surface is exposed going forward), or
2. Detect that the installed typescript is the native-only 7.0 package and emit a clear, actionable message (e.g. "TypeScript 7.0's native port is not yet supported; pin typescript@^6 or use @typescript/native-preview alongside it") instead of the misleading "package not installed" error.

[icyJoseph]

I haven't looked to much into the root issue here, but I don't think 1 is actionable just yet? We need the 7.1 release (the one with the API)

I think you should be able to work with this, as per the release post https://devblogs.microsoft.com/typescript/announcing-typescript-7-0/#running-side-by-side-with-typescript-6.0 :

   "typescript": "npm:@typescript/typescript6@6.0.1"

I'll give it a go in a create-next-app project.

[abhishekmardiya]

Thanks — that works. Worth noting the alias alone drops the native compiler, since @typescript/typescript6 ships its binary as tsc6, not tsc. Aliasing both ways keeps both:

{
  "devDependencies": {
    "typescript": "npm:@typescript/typescript6@^6.0.2",
    "@typescript/native": "npm:typescript@^7.0.2"
  }
}

node_modules/typescript is TS 6 (the JS API Next.js resolves), TS 7 sits under a different folder name, and the binaries don't collide — npx tsc is the Go compiler, npx tsc6 the old one. next build's type check still runs on TS 6 semantics either way, so the speedup only lands where you invoke tsc directly.

[icyJoseph]

Yes, as the post says. I did a little benchmark though, and the out of the box create-next-app went from ~900ms to ~300ms - wild stuff.

We will post more shortly.

[icyJoseph]

Ok so this landed #95639 - Waiting for a next@canary cut containing it!!

You can read the docs on the PR, but basically, install typescript@7, and enable this experimental flag.