Decorators

Every decorator green-tea exports, grouped by where it applies. All require experimentalDecorators: true in your tsconfig — see Why legacy decorators.

Structure

@Module(options)

Marks a class as a module and records what it wires together.

@Module({
  mountpoint: '/api',        // path prefix for this module's controllers (required)
  providers: [Database],     // app-scope @Provider classes
  steps: [Authenticate],     // request-scope @Step classes
  controllers: [UserCtl],    // @Route classes
})
class ApiModule {}

@Route(prefix)

Marks a class as a controller; prefix is prepended to each route path.

Providers & steps

@Provider(options)

An app-scope value, built once at boot and cached, addressable by provides.

Option	Type	Default	Meaning
provides	string	—	the token this provider produces (required)
needs	string[]	[]	tokens it depends on
optional	boolean	false	if it throws on boot, degrade instead of aborting (details)
export	boolean	false	expose over the mesh control channel (mesh)

@Step(options)

A request-scope transform that merges keys into the context. Same options as @Provider.

@Transformer(fn)

Method decorator. Turns a handler’s return value into { status?, headers?, body }. JsonTransformer is the default.

@Html / @Html(path, opts?)

Method decorator. Marks a buffered GET/POST handler as serving HTML instead of going through the JSON transformer. Three modes (details):

Form	Behavior
@Html (bare)	sends the handler’s returned string as text/html
@Html('file.html')	serves that file verbatim; the handler’s return value is ignored
@Html('file.html', { template: true })	renders the file with the handler’s returned data, via the built-in render engine or viewEngine (createApp)

Only buffered GET/POST routes are supported, and @Html can’t be combined with @Transformer on the same handler — both are validated at boot, not per-request.

Routes

Method decorators on a controller. All accept (path, opts?) where opts = { export?: boolean, duplicates?: 'array' | 'last', maxBodyBytes?: number, maxParts?: number }. maxBodyBytes / maxParts override the server-wide limits for this route only.

Decorator	Method	Transport
@Get @Head @Post @Put @Patch @Delete @Options	as named	buffered response
@Sse	GET	text/event-stream
@Ws	GET	WebSocket duplex
@Stream	GET	negotiated (SSE / ndjson / WS)

@Get('/ping', { export: true })                          // exportable over mesh
@Post('/upload', { duplicates: 'array' })                // repeated form fields → arrays
@Post('/avatar', { maxBodyBytes: 5_000_000, maxParts: 20 }) // per-route upload limits

See Routing for pattern matching and Streaming for the transports.

@Head and @Options declare explicit handlers. When they are absent, the router can provide an implicit buffered-GET HEAD response or an automatic 204 OPTIONS response; those fallbacks are runtime behavior, not decorator metadata.

Arguments

A handler’s signature declares exactly what it wants, in any order.

Decorator	Injects	Forms
@needs('user')	a graph-produced value (boot-validated)	('key')
@ctx()	the whole accumulated context	()
@param(...)	route params	() · ('id') · ('id', schema)
@query(...)	parsed query string	() · ('q') · (['a','b']) · (schema)
@body(...)	parsed body (JSON / urlencoded / multipart)	() · ('field') · (schema)
@headers(...)	request headers (whole bag or picked)	() · ('authorization') · (['a','b']) · (schema)
@header('name')	one request header (singular alias of @headers)	('x-trace') · ('x-count', schema)
@inbound()	the incoming message stream (WebSocket)	()
@abort()	the request’s AbortSignal	()

Passing a Standard Schema validates and coerces the value before the handler sees it. Full details in Argument decorators.