HandlerMetadataStorage

Kind: Class

Source: packages/core/helpers/handler-metadata-storage.ts

Part of: Core

HandlerMetadataStorage associates metadata values with handler functions and provides lookup access later in the execution flow. It is useful for preserving handler-specific configuration discovered during registration, decoration, or route setup.

Methods

Diagram

mermaid
graph LR
  A[Handler function] -->|set(handler, metadata)| B[HandlerMetadataStorage]
  B -->|stores association| C[Metadata value]
  A -->|get(handler)| B
  B -->|returns TValue or undefined| D[Consumer / runtime logic]

Usage

ts
import { HandlerMetadataStorage } from './helpers/handler-metadata-storage';

type HandlerOptions = {
  requiresAuth: boolean;
  rateLimit?: number;
};

const handlerMetadata = new HandlerMetadataStorage<HandlerOptions>();

function getProfile() {
  return { id: 'user-123' };
}

handlerMetadata.set(getProfile, {
  requiresAuth: true,
  rateLimit: 100,
});

const options = handlerMetadata.get(getProfile);

if (options?.requiresAuth) {
  // Apply authentication middleware or authorization checks.
}

console.log(options);
// { requiresAuth: true, rateLimit: 100 }

AI Coding Instructions

• Use the same handler reference for both set() and get(); a different function instance will not resolve the stored metadata.
• Treat get() results as optional, since it returns undefined when no metadata has been registered.
• Store small, immutable configuration objects where possible so handler metadata remains predictable across the application lifecycle.
• Register metadata during handler setup or discovery, then read it from routing, middleware, or invocation logic.

Used by

2 references from 2 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

Imported by (2)

• RpcHandlerMetadata — packages/microservices/context/rpc-context-creator.ts:35
• WsHandlerMetadata — packages/websockets/context/ws-context-creator.ts:34