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@json-express/adapter-memory ​

Official ephemeral RAM database adapter for JSONExpress.

The @json-express/adapter-memory package is an implementation of IDatabaseAdapter that stores all application data purely in system RAM using JavaScript Maps.

Because it never touches the disk or requires a network connection, it is blazingly fast. However, all data is permanently lost when the Node.js server restarts.

Installation ​

bash
npm install @json-express/adapter-memory

Configuration ​

The adapter is auto-discovered by the json-express runtime — installing the package is the entire configuration. It is the default adapter shipped with @json-express/boot.

bash
npm install @json-express/adapter-memory
npx json-express

If you have multiple adapters installed (e.g. adapter-memory alongside adapter-json), pick one in .env:

bash
jex.adapter=@json-express/adapter-memory

Core Features ​

1. Isolated E2E Testing Environment ​

The primary use case for adapter-memory is automated testing.

If you are running a Playwright or Vitest E2E suite, you do not want your tests colliding with each other or polluting a real database. By spinning up JSONExpress with the MemoryAdapter before each test suite, you guarantee a pristine, isolated, and incredibly fast database environment for every single test run.

2. Rapid API Scaffolding ​

When you are first building a frontend application (like a React or Vue dashboard), you often just need a "fake" backend to build against.

By running JSONExpress with the MemoryAdapter and the @json-express/seeder-faker utility, you can instantly spin up thousands of realistic mock records in RAM without worrying about database migrations or cleaning up junk data later.

3. Guaranteed Enterprise Parity ​

You might wonder: "If I test my app using RAM, how do I know it will work in production with PostgreSQL?"

This adapter is strictly verified against the internal Adapter Compliance Suite. It guarantees 100% feature parity with enterprise SQL adapters. If you issue a GET /albums?_expand=artist, the MemoryAdapter will perform the exact same foreign-key resolution logic as a real SQL join. If you insert a duplicate email, it will throw the exact same UniqueConstraintError.

  • @json-express/core: Run the runAdapterComplianceTests from the core testing utilities to verify adapter behavior.
  • @json-express/adapter-json: Swap to the JSON file adapter if you want your mock data to survive server restarts!