Prisma is a popular ORM for JavaScript and TypeScript, but sharing an instance of it between multiple microservices can be tricky. Here's a solution to this problem that avoids the maintainability nightmare of copy-pasting the Prisma schema into all of your projects.

## **Setting Up a New Project**

\
To start, create a new project and follow the Prisma Quickstart instructions. Alternatively, you can use the following commands:

```bash
mkdir prisma-instance
cd prisma-instance
pnpm init
pnpm add prisma typescript ts-node @types/node -D
npx tsc --init
pnpm prisma init
pnpm add @prisma/client
```

Next, copy your existing Prisma folder containing your schema and migrations (if applicable) from your project to **the root** of the new project.

Then, update your **`tsconfig.json`** file as follows:

```json
{
  "compilerOptions": {
    "sourceMap": true,
    "outDir": "dist",
    "strict": true,
    "lib": ["esnext"],
    "esModuleInterop": true
  }
}
```

Inside your **`schema.prisma`** file, add **`output = "client"`** to the **`generator`**:

```javascript
generator client {
    provider = "prisma-client-js"
    output   = "client"
}
```

Run **`npx prisma generate`**, which will create a **`client`** directory inside your **`prisma`** directory with the generated client inside it.

Next, create a **`src`** directory in the root of your project and add an **`index.ts`** and **`index.d.ts`** file:

```javascript
import { PrismaClient } from '../prisma/client';

let prisma: PrismaClient | undefined;

export const getPrisma = () => {
  if (!prisma) {
    prisma = new PrismaClient();
  }
  return prisma;
};
```

```javascript
import { PrismaClient } from '../prisma/client';

export * from '../prisma/client/index.d';
export function getPrisma(): PrismaClient;
```

Add a **`postinstall`** script to your **`package.json`** file:

```json
"scripts": {
    "postinstall": "tsc && cp src/index.d.ts dist/index.d.ts && npx prisma@4.7.1 generate"
}
```

Finally, publish your private package using **[npm](https://docs.github.com/en/packages/quickstart)** or **[GitHub](https://dev.to/rajandmr/publishing-private-npm-package-for-free-nd7)**.

## **Using the Private Prisma Package in Next.js**

If one of the projects you plan to use Prisma in is a Next.js project, you may encounter some issues. To resolve them:

1. Install the private package with **`pnpm add @your-name/prisma-instance`**.

2. In your **`.npmrc`** file, add these two lines:

```bash
public-hoist-pattern[]=*prisma*
node-linker=hoisted
```

1. If you’re using the **`app`** directory in Next 13, open your **`next.config.js`** and add your Prisma package to **`serverComponentsExternalPackages`**:

```javascript
experimental: {
    appDir: true,
    serverComponentsExternalPackages: ['@your-name/prisma-instance'],
  },
```

With these steps, you should now be able to share a single instance of Prisma between multiple microservices, improving the maintainability of your projects. Happy coding!

Sharing a Prisma Instance Between Projects

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