nats-micro/src/decorators/middleware.ts

NATS micro compatible extra-lightweight microservice library

/* eslint-disable @typescript-eslint/no-explicit-any */
import { storage } from './storage.js';
import { MethodDescriptor, Middleware } from '../types/index.js';

function middleware<
  T = void,
  R = void,
>(middlewares: Middleware<T, R>[], postMiddlewares: Middleware<T, R>[] = []) {

  return <D extends MethodDescriptor<T, R>>(
    target: unknown,
    key: string | symbol,
    descriptor: D,
  ): D => {

    if (!descriptor.value)
      throw new Error('Use method decorators only on class methods');

    const storedMethod = storage.ensureClassMethodAdded<T, R>(target, descriptor.value);
    storedMethod.config = {
      ...storedMethod.config,
      middlewares: [...(storedMethod.config.middlewares ?? []), ...middlewares],
      postMiddlewares: [...(storedMethod.config.postMiddlewares ?? []), ...postMiddlewares],
    };

    return descriptor;
  };
}

middleware.pre = <
  T = void,
  R = void,
>(...middlewares: Middleware<T, R>[]) => middleware(middlewares, []);

middleware.post = <
  T = void,
  R = void,
>(...middlewares: Middleware<T, R>[]) => middleware([], middlewares);

export {
  middleware,
};