Why doesn't extensionless imports work when the generated prisma client uses extensionless imports?

[m2x07]

Question

Following the quickstart guide of prisma with the sqlite db, there is a section in docs which gives us certain options to use in our tsconfig.json

{
  "compilerOptions": {
    "module": "ESNext",
    "moduleResolution": "bundler",
    "target": "ES2023",
    "strict": true,
    "esModuleInterop": true,
    "ignoreDeprecations": "6.0"
  }
}

applying those options, can build the codebase correctly (through npx tsc) however, running the compiled bundle with node causes it to throw error ERR_MODULE_NOT_FOUND for every imports. including imports made by the generated prisma client and any other module imports of our own in the code. Why does this happen?
Nodejs version: v25.0.0
tsc version: v6.0.2

How to reproduce (optional)

Expected behavior (optional)

No response

Information about Prisma Schema, Client Queries and Environment (optional)

// Add your schema.prisma

// Add any relevant Prisma Client queries here

• OS:

• Database:

• Node.js version:

• Run prisma -v to see your Prisma version and paste it

[everton-dgn]

This isn't really a Prisma issue, it's the moduleResolution: "bundler" setting doing what it's supposed to.

bundler is designed for bundler-driven workflows (Vite, esbuild, webpack). Under that setting, TypeScript accepts extensionless imports and does not rewrite them on emit. Node.js ESM at runtime requires explicit .js extensions for relative imports, and since nothing in the build adds them, Node throws ERR_MODULE_NOT_FOUND on every first-party import the moment you run the compiled output.

Three ways to fix it, pick one:

1. Run TypeScript directly with tsx (simplest for the Prisma quickstart)

npx tsx src/index.ts

No build step, no resolution mismatch. This is what most starter projects use.

2. Switch to nodenext

{
  "compilerOptions": {
    "module": "NodeNext",
    "moduleResolution": "nodenext",
    "target": "ES2023",
    "strict": true,
    "esModuleInterop": true
  }
}

With nodenext, TypeScript requires .js extensions in your imports (import { foo } from './bar.js'), the emitted code then runs on Node without rewrites. Note: this only affects your own imports; the generated Prisma client works either way.

3. Compile to CommonJS

{
  "compilerOptions": {
    "module": "CommonJS",
    "moduleResolution": "node",
    "target": "ES2023",
    "strict": true,
    "esModuleInterop": true
  }
}

Easiest for short scripts since CJS resolution doesn't care about extensions.

Summary: moduleResolution: "bundler" isn't meant for code that runs directly via node. Use tsx to run TS, or switch both module and moduleResolution to a Node-compatible pair and the Prisma client imports will resolve cleanly too.

[m2x07]

switching to nodenext didn't work either. still had the same error for my imports, as well as prisma's imports

using tsx can work, however there is an official solution for this. we can update our schema.prisma file to reflect the following:

generator client {
    importFileExtension = "js"
}

this makes sure that when we generate our prisma client, it includes the specified file extension in it's import statements
https://www.prisma.io/docs/orm/reference/prisma-schema-reference#fields-for-prisma-client-provider