@prisma/client 6.19.0: Prisma.defineExtension, PrismaClient

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/%40prisma/client@6.19.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40prisma/client@6.19.0
Demonstrate these symbols/APIs:
  - @prisma/client.Prisma.defineExtension
  - @prisma/client.PrismaClient

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:532de4451a669f64d5467f5f1d8659d805cc3f98dcfaf04778d277584e7a1764","contract":["PrismaClient constructor throws an Error explaining client must be generated when instantiated before prisma generate","Prisma.prismaVersion exposes pinned client version 6.19.0 and engine commit hash","Prisma.defineExtension preserves and returns a function extension directly","Prisma.defineExtension wraps an extension object into an extension installer that calls client.$extends","Prisma.getExtensionContext returns the target client or model extension context"],"goal":"verify pkg:npm/%40prisma/client@6.19.0","kind":"HOW","packages":["pkg:npm/%40prisma/client@6.19.0"],"schemaVersion":1,"symbols":["@prisma/client.Prisma.defineExtension","@prisma/client.PrismaClient"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40prisma/client@6.19.0"],"schemaVersion":1,"subject":"pkg:npm/%40prisma/client@6.19.0","symbols":["@prisma/client.Prisma.defineExtension","@prisma/client.PrismaClient"],"verifierAdapter":"node-typescript@1"}

import fs from 'node:fs';
import path from 'node:path';
import { execSync } from 'node:child_process';

const dotPrismaPath = path.resolve('node_modules/.prisma/client/default.js');
if (!fs.existsSync(dotPrismaPath)) {
  const postinstallPath = path.resolve('node_modules/@prisma/client/scripts/postinstall.js');
  if (fs.existsSync(postinstallPath)) {
    execSync(`node "${postinstallPath}"`, { stdio: 'pipe' });
  }
}

const pkg = (await import('@prisma/client')).default;
export const { Prisma, PrismaClient } = pkg;
export default PrismaClient;

{
  "name": "sample-prisma-client",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-prisma-client",
      "version": "1.0.0",
      "dependencies": {
        "@prisma/client": "6.19.0"
      }
    },
    "node_modules/@prisma/client": {
      "version": "6.19.0",
      "resolved": "https://registry.npmjs.org/@prisma/client/-/client-6.19.0.tgz",
      "integrity": "sha512-QXFT+N/bva/QI2qoXmjBzL7D6aliPffIwP+81AdTGq0FXDoLxLkWivGMawG8iM5B9BKfxLIXxfWWAF6wbuJU6g==",
      "hasInstallScript": true,
      "license": "Apache-2.0",
      "engines": {
        "node": ">=18.18"
      },
      "peerDependencies": {
        "prisma": "*",
        "typescript": ">=5.1.0"
      },
      "peerDependenciesMeta": {
        "prisma": {
          "optional": true
        },
        "typescript": {
          "optional": true
        }
      }
    }
  }
}

{
  "name": "sample-prisma-client",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "@prisma/client": "6.19.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40prisma/client@6.19.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40prisma/client@6.19.0"
  ],
  "symbols": [
    "@prisma/client.Prisma.defineExtension",
    "@prisma/client.PrismaClient"
  ]
}

import assert from 'node:assert/strict';
import { Prisma, PrismaClient } from '../index.mjs';

// Contract 1: PrismaClient constructor throws an Error explaining client must be generated when instantiated before prisma generate
{
  assert.strictEqual(typeof PrismaClient, 'function');
  assert.throws(
    () => new PrismaClient(),
    (err) => {
      assert(err instanceof Error);
      assert.match(err.message, /@prisma\/client did not initialize yet/);
      assert.match(err.message, /prisma generate/);
      return true;
    }
  );
}

// Contract 2: Prisma.prismaVersion exposes pinned client version 6.19.0 and engine commit hash
{
  assert.strictEqual(typeof Prisma.prismaVersion, 'object');
  assert.strictEqual(Prisma.prismaVersion.client, '6.19.0');
  assert.strictEqual(typeof Prisma.prismaVersion.engine, 'string');
  assert.ok(Prisma.prismaVersion.engine.length > 0);
}

// Contract 3: Prisma.defineExtension preserves and returns a function extension directly
{
  const customExtension = (client) => client;
  const result = Prisma.defineExtension(customExtension);
  assert.strictEqual(result, customExtension);
}

// Contract 4: Prisma.defineExtension wraps an extension object into an extension installer that calls client.$extends
{
  const extConfig = {
    name: 'custom-extension',
    result: {
      user: {
        computedField: {
          needs: { id: true },
          compute(user) {
            return `id-${user.id}`;
          },
        },
      },
    },
  };

  const extensionFn = Prisma.defineExtension(extConfig);
  assert.strictEqual(typeof extensionFn, 'function');

  let passedArg = null;
  const mockClient = {
    $extends(arg) {
      passedArg = arg;
      return this;
    },
  };

  const extended = extensionFn(mockClient);
  assert.strictEqual(extended, mockClient);
  assert.strictEqual(passedArg, extConfig);
}

// Contract 5: Prisma.getExtensionContext returns the target client or model extension context
{
  const ctx = { modelName: 'User', operation: 'findUnique' };
  const returned = Prisma.getExtensionContext(ctx);
  assert.strictEqual(returned, ctx);
}

console.log('All contracts passed.');