Decorator reference

Legacy TypeScript class, method, and parameter decorators for declarative Fetcher services.

Installation and runtime

pnpm add @ahoo-wang/fetcher-decorator @ahoo-wang/fetcher

Enable legacy TypeScript decorators in the consuming project: experimentalDecorators: true and emitDecoratorMetadata: true. reflect-metadata is a regular dependency imported by the package; it is installed automatically.

Version 5.0.0 declares Node >=18.20.8 for consumers. Repository development has a separate Node >=20.20.2 / pnpm 10.34.5 requirement. Browser/runtime APIs used by a feature must also exist; the engine range is not a promise that every Web API (for example Response.bytes) is available.

Choose an entry point

Use @api plus method decorators for a hand-written service. Use @path/@query/@body for stable arguments and @request for per-call transport options. Use lifecycle hooks for service-specific exchange work; shared transport policy belongs in Fetcher interceptors. Generated services use the same runtime contract.

Choose a topic

Topic	Use it for
Services and endpoints	Use legacy TypeScript decorators to replace service methods with Fetcher requests. Enable experimentalDecorators and emitDecoratorMetadata (matching this package's tsconfig); stage-3 decorators do not support this parameter-decorator contract. The package imports reflect-metadata itself.
Parameter binding	Parameter decorators bind arguments by index, not by their declared TypeScript type. Explicit names survive minification and are the reliable choice for path/query/header fields.
Metadata and execution lifecycle	Decorated methods resolve a fresh exchange for each call while reusing a per-instance, per-method executor. Hooks run on the service instance, so avoid storing mutable per-request state on that instance when calls can overlap.

Minimal complete example

import { Fetcher } from '@ahoo-wang/fetcher';
import {
  api,
  get,
  path,
  autoGeneratedError,
} from '@ahoo-wang/fetcher-decorator';

type User = { id: string; name: string };
const client = new Fetcher({
  baseURL: 'https://api.example.com',
  timeout: 3000,
});
@api('/users', { fetcher: client })
class Users {
  @get('/{id}')
  find(@path('id') id: string): Promise<User> {
    throw autoGeneratedError(id);
  }
}
const users = new Users();
// Requires a service returning JSON at https://api.example.com/users/1.
async function loadUser() {
  return await users.find('1');
}
void loadUser;

Complete public symbol index