# Platform Fastify

### What it is responsible for

Platform Fastify manages the Fastify-facing work entry points named `FastifyAdapter`, `MiddlewareFn`, and `FASTIFY_ROUTE_CONFIG_METADATA`. Its documented surface is tied to Nest, which the authors describe as a framework for building Node.js server-side applications. The available evidence identifies these symbols as the paths through which work enters this subsystem, without describing their internal control flow or integration details.

### What it refuses

Platform Fastify rejects a version constraint when its value is neither a string nor an array of strings. The rejection message is: “Version constraint should be a string or an array of strings.”

### Notable members

- `FastifyAdapter` is a named entry point for work entering Platform Fastify.
- `MiddlewareFn` is another named entry point for work entering the subsystem.
- `FASTIFY_ROUTE_CONFIG_METADATA` is a named constant and work-entry symbol; the evidence does not state its stored value or how consumers interpret it.

44 entities in `packages/platform-fastify`. Nothing else in this repository depends on it.

## What it is made of

Its 44 entities sit in 11 files under `packages/platform-fastify`: 29 doc comments, 5 interfaces, 3 constants, 3 functions and 4 more.
`constants.ts` holds 3 of them — more than any other file here.
`FastifyAdapter` declares 50 methods, the widest surface here.

## Where work enters

- `Readme.md` — `packages/platform-fastify/Readme.md`:1
- `FastifyAdapter` — `packages/platform-fastify/adapters/fastify-adapter.ts`:124
- `MiddlewareFn` — `packages/platform-fastify/adapters/middie/fastify-middie.ts`:17
- `FASTIFY_ROUTE_CONFIG_METADATA` — `packages/platform-fastify/constants.ts`:1

## How it refuses and fails

1 of its components records a refusal or a failure handler.
It refuses work outright, under a condition written into the component itself.
Its `catch` blocks handle a failure that already happened in 2 places.