PrismaP
Prisma•2y ago•
18 replies
neofrog.

Prisma type inference is returning weird types

I'm encountering an issue with TypeScript not properly inferring the types when using PrismaClient in my Node.js typescript application.

Setup:

Prisma Schema:

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

model Account {
  id                String   @id @default(uuid())
  telegram_id       BigInt   @unique
  telegram_username String?  @unique
}


Prisma Client Initialization:

import { PrismaClient } from "@prisma/client";

const prisma = new PrismaClient();
export default prisma;
Issue:


When I perform a simple findUnique query, TypeScript infers the type as PrismaAccountClient<Account | null> instead of the expected model type.

const getAccount = async (telegram_id: number) => {
    const account = await prisma.account.findUnique({
        where: { telegram_id: telegram_id.toString() },
    });

    return account;
};

// Testing type inference
const testTypeInference = async () => {
    const account = await getAccount(123456);

    if (account) {
        // TypeScript should infer that account is of type Account
        // but instead it infers a complex Prisma type
        console.log(account.telegram_username);
    }
};

testTypeInference();


Expected Type:

account should be inferred as Account | null.

Actual Type:

account is inferred as PrismaAccountClient<Account | null>.
Question:

How can I ensure that TypeScript infers the correct type (Account | null) for the result of the findUnique query without needing to manually set the types?

Any help would be greatly appreciated!
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