Handling exceptions and errors - Prisma

In order to handle different types of errors you can use instanceof to check what the error is and handle it accordingly.

The following example tries to create a user with an already existing email record. This will throw an error because the email field has the @unique attribute applied to it.

prisma

model User {
  id    Int     @id @default(autoincrement())
  email String  @unique
  name  String?
}

Use the Prisma namespace to access the error type. The error code can then be checked and a message can be printed.

import { PrismaPg } from "@prisma/adapter-pg";
import { PrismaClient, Prisma } from "../generated/prisma/client";

const connectionString = `${process.env.DATABASE_URL}`;
const adapter = new PrismaPg({ connectionString });
const prisma = new PrismaClient({ adapter });

try {
  await client.user.create({ data: { email: "[email protected]" } });
} catch (e) {
  if (e instanceof Prisma.PrismaClientKnownRequestError) {
    // The .code property can be accessed in a type-safe manner
    if (e.code === "P2002") {
      console.log(
        "There is a unique constraint violation, a new user cannot be created with this email",
      );
    }
  }
  throw e;
}

See Errors reference for a detailed breakdown of the different error types and their codes.