Documenting Typing the Extended PrismaClient

[NGimbal]

I've been running into an issue where the VSCode Typescript errors with errors like the following:

Excessive stack depth comparing types...

This expression is not callable....

After searching and consulting with various AI oracles I realized the issue could be solved by removing the prisma-field-encryption extension. This Github issue was a hint, although the discussion is from when clientExtensions were a preview feature.

prisma/prisma#17236

The solution seems to be the following:

import { PrismaClient } from '@prisma/client'
import { fieldEncryptionExtension } from 'prisma-field-encryption'
import { type PrismaClientExtends } from '@prisma/client/extension'
import type * as runtime from '@prisma/client/runtime/library'

// Define the extended client type using Prisma's extension type system
type ExtendedClient = PrismaClient & PrismaClientExtends<runtime.Types.Extensions.DefaultArgs>

const globalClient = new PrismaClient()

export const client = globalClient.$extends(
  // This is a function, don't forget to call it:
  fieldEncryptionExtension()
) as ExtendedClient

export type { ExtendedClient as PrismaClient }

Does this fix make sense? It is working nicely for me. If so I'd like to open a PR to add this to the Readme. 🙏

[franky47]

Yes I think that would be a good addition, thanks!

I had to do something similar in the integration tests, though my use-case was getting the same type for a client using the middleware approach and one with the extension approach:

prisma-field-encryption/src/tests/prismaClient.ts

Line 21 in 8380200

return client.$extends(fieldEncryptionExtension(config)) as PrismaClient