The squasher folds compatible ALTER TABLE operations into the originating CREATE TABLE so output is a compact schema baseline (instead of appending retained statements).

Requirements

• Node.js 18.18+ or Bun
• A Prisma project with a migrations directory such as prisma/migrations
• If you plan to run the generated Prisma metadata sync helper: prisma and @prisma/client

Install

Run without installing:

npx pattypan

If you use Bun:

bunx pattypan

Install globally with npm:

npm install -g pattypan

Then run it as:

pattypan prisma/migrations

Usage

Primary workflow (boundary-based quick pick):

npx pattypan prisma/migrations

Or, if installed globally:

pattypan prisma/migrations

In quick mode, you:

1. Pick one boundary migration from a newest-first list (page size 5).
2. Tool auto-selects that migration plus all newer migrations.
3. Tool opens a prechecked cherry-pick list where you can uncheck any items.

Non-interactive boundary workflow:

npx pattypan prisma/migrations --from 20240115094500_add_orders

You can also pass a unique fragment:

npx pattypan prisma/migrations --from add_orders

Optional additive exclusions (applied after boundary selection):

npx pattypan prisma/migrations --from add_orders --exclude production_20240101,production_20240115

Useful options:

• --from <migration>: boundary migration name or unique fragment
• --exclude <patterns>: comma-separated migration filters to skip
  • supports * wildcard, otherwise substring matching
• --yes, -y: skip confirmation prompt
• --remove-dml: strip INSERT, UPDATE, and DELETE statements from the squashed output
• --name <migration_name>: set output migration directory name
• --latest, -n <count>: legacy selection mode for latest N migrations
• --allow-gaps: legacy latest mode only

If selected migrations contain data-migration statements (INSERT, UPDATE, or DELETE), Pattypan keeps them by default. Interactive runs offer a prompt to remove them, and non-interactive runs can opt in with --remove-dml.

Output

Each squash writes:

• a new squashed migration.sql inside the selected output migration directory
• a companion syncPrismaMigrations.ts file in the migrations directory root

The generated syncPrismaMigrations.ts helper is intended for existing databases where you need to replace the selected _prisma_migrations rows with the new squashed migration entry.

Development

If you are working on Pattypan itself:

bun install

bun run build

bun test

Interactive modes:

• quick mode: pick boundary migration (recommended)
• manual mode: checkbox migration selection