`@prisma/adapter-pg` `Bytes` field fails in jsdom environment due to cross-realm `instanceof Uint8Array` check

[adri1wald]

Bug description

When running tests with Vitest in jsdom environment, reading or writing Bytes fields fails with:

Expected a byte array in column 'value', got object: <content>

This happens because jsdom creates its own JavaScript realm with separate built-in classes. A Uint8Array created in jsdom's realm fails instanceof Uint8Array checks in Node's realm where @prisma/adapter-pg runs.

Severity

🔹 Minor: Unexpected behavior, but does not block development

Reproduction

https://github.com/adri1wald/prisma-jsdom-bytes-issue

1. Create a Vitest config with environment: 'jsdom'
2. Use @prisma/adapter-pg with a model containing a Bytes field
3. Create/read a record with Buffer.from('test') or new TextEncoder().encode('test')
4. Observe the error

Expected vs. Actual Behavior

• Expected: Bytes fields work the same as in Node environment
• Actual: Fails with "Expected a byte array in column 'value', got object"

Frequency

Consistently reproducible

Does this occur in development or production?

Only in development (e.g., CLI tools, migrations, Prisma Studio)

Is this a regression?

Likely introduced with Prisma 7

Workaround

Add // @vitest-environment node directive to test files, or configure Vitest to use node environment for server tests

Prisma Schema & Queries

model ProjectContext {
  id        String   @id @default(cuid())
  value     Bytes
  // ...
}

await prisma.projectContext.create({
  data: { value: Buffer.from('test content') }
})

Prisma Config

// Add your `prisma.config.ts`

Logs & Debug Info

// Debug logs here

Environment & Setup

OS: macOS
Database: PostgreSQL
Node.js version: 24.x
Test runner: Vitest 4.x with jsdom

Prisma Version

7.3.0