prisma-client provider and vanilla JS support?

[M1CK431]

Bug description

As stated on the official Prisma website, both Javascript (aka "vanilla") and TypeScript are supported languages.

However, while trying prisma-client provider with generatedFileExtension = "js", generated files are still using TypeScript (despite .js extension) and so can't be used in vanilla JS files.

Severity

🔹 Minor: Unexpected behavior, but does not block development

Reproduction

Not relevant

Expected vs. Actual Behavior

Expected: generatedFileExtension = "js" should generate vanilla JS files
Actual: TypeScript files with .js generated

Frequency

Consistently reproducible

Does this occur in development or production?

Both development and production

Is this a regression?

No since related to an "Early Access" feature.

Workaround

Remain on prisma-client-js provider

Prisma Schema & Queries

Not relevant.

Prisma Config

Not relevant

Logs & Debug Info

Not relevant

Environment & Setup

• OS: Archlinux
• Database: SQLite
• Node.js version: v24.2.0

Prisma Version

From package.json:

{
  "prisma": "^6.10.1"
  "@prisma/adapter-better-sqlite3": "^6.10.1",
  "@prisma/client": "^6.10.1",
}

[M1CK431]

Answer to myself: node --experimental-transform-types index.js
And in index.js we can now import { PrismaClient } from './generated/prisma/client.ts';
Obviously this is just a workaround but still might be useful for others.

NB: --experimental-transform-types is available only from node v22.7+. Use tsx as an alternative for previous version.

[jkomyno]

Hey @M1CK431, the new prisma-client generator emits TypeScript files only, and it does so by design.
The generatedFileExtension configuration attribute doesn't support js, but it supports ts, mts, cts.
See docs.

As stated on the official Prisma website, both Javascript (aka "vanilla") and TypeScript are supported languages.

The statement is true for Prisma 6, as prisma-client-js still exists, regardless of the design choices of the new prisma-client generator :)

---

The idea is that the generated Prisma Client files become part of your own codebase, rather than being hidden within node_modules. This allows you to bundle and transpile them however you see fit, which in turn avoids a plethora of failing edge cases on modern frameworks.

I'd always recommend bundling your app in production, but if you want to run Prisma locally without compiling TypeScript to JavaScript, and without using node --experimental-transform-types, I'd recommend using bun or deno, depending on your use case and how many Node.js-centric features your app relies on.