<TopBlock>

As your application grows, you may find the need to group related logic together. We suggest either:

- Creating static methods using a [Prisma Client extension](/orm/prisma-client/client-extensions)
- Wrapping a model in a class
- Extending Prisma Client model object

</TopBlock>

## Static methods with Prisma Client extensions

The following example demonstrates how to create a Prisma Client extension that adds a `signUp` and `findManyByDomain` methods to a User model.

<TabbedContent code>

<TabItem value="Prisma Client extension">

```tsx
import bcrypt from 'bcryptjs'
import { PrismaClient } from '../prisma/generated/client'

const prisma = new PrismaClient().$extends({
  model: {
    user: {
      async signUp(email: string, password: string) {
        const hash = await bcrypt.hash(password, 10)
        return prisma.user.create({
          data: {
            email,
            password: {
              create: {
                hash,
              },
            },
          },
        })
      },

      async findManyByDomain(domain: string) {
        return prisma.user.findMany({
          where: { email: { endsWith: `@${domain}` } },
        })
      },
    },
  },
})

async function main() {
  // Example usage
  await prisma.user.signUp('user2@example2.com', 's3cret')

  await prisma.user.findManyByDomain('example2.com')
}
```

</TabItem>

<TabItem value="Prisma schema">

```prisma file="prisma/schema.prisma" copy 
datasource db {
  provider = "postgresql"
}

generator client {
  provider = "prisma-client"
  output   = "./generated"
}

model User {
  id       String    @id @default(cuid())
  email    String
  password Password?
}

model Password {
  hash   String
  user   User   @relation(fields: [userId], references: [id], onDelete: Cascade)
  userId String @unique
}
```

</TabItem>

</TabbedContent>

## Wrap a model in a class

In the example below, you'll see how you can wrap the `user` model in the Prisma Client within a `Users` class.

```tsx
import { PrismaClient, User } from '@prisma/client'

type Signup = {
  email: string
  firstName: string
  lastName: string
}

class Users {
  constructor(private readonly prismaUser: PrismaClient['user']) {}

  // Signup a new user
  async signup(data: Signup): Promise<User> {
    // do some custom validation...
    return this.prismaUser.create({ data })
  }
}

async function main() {
  const prisma = new PrismaClient()
  const users = new Users(prisma.user)
  const user = await users.signup({
    email: 'alice@prisma.io',
    firstName: 'Alice',
    lastName: 'Prisma',
  })
}
```

With this new `Users` class, you can define custom functions like `signup`:

Note that in the example above, you're only exposing a `signup` method from Prisma Client. The Prisma Client is hidden within the `Users` class, so you're no longer be able to call methods like `findMany` and `upsert`.

This approach works well when you have a large application and you want to intentionally limit what your models can do.

## Extending Prisma Client model object

But what if you don't want to hide existing functionality but still want to group custom functions together? In this case, you can use `Object.assign` to extend Prisma Client without limiting its functionality:

```tsx
import { PrismaClient, User } from '@prisma/client'

type Signup = {
  email: string
  firstName: string
  lastName: string
}

function Users(prismaUser: PrismaClient['user']) {
  return Object.assign(prismaUser, {
    /**
     * Signup the first user and create a new team of one. Return the User with
     * a full name and without a password
     */
    async signup(data: Signup): Promise<User> {
      return prismaUser.create({ data })
    },
  })
}

async function main() {
  const prisma = new PrismaClient()
  const users = Users(prisma.user)
  const user = await users.signup({
    email: 'alice@prisma.io',
    firstName: 'Alice',
    lastName: 'Prisma',
  })
  const numUsers = await users.count()
  console.log(user, numUsers)
}
```

Now you can use your custom `signup` method alongside `count`, `updateMany`, `groupBy()` and all of the other wonderful methods that Prisma Client provides. Best of all, it's all type-safe!

## Going further

We recommend using [Prisma Client extensions](/orm/prisma-client/client-extensions) to extend your models with [custom model methods](https://github.com/prisma/prisma-client-extensions/tree/main/instance-methods).

---

# Case sensitivity