xloop

xloop

Add sugar & enhanced APIs inspired by NestJS to Loopback v4

Installation

• Nodejs >= 10
• Loopback 4

npm install xloop

API Reference

• HTTP Decorators
  • @http.request()
  • @http.response()
  • @http.header(string, string)
  • @http.status(number)
  • @http.context()
• Custom Error Codes

HTTP Decorators

HTTP decorators are used to annotate controller methods.

@http.request()

Decorate a param of a controller method to get the request object.

import { http } from 'xloop/decorators';

export class SomeController {
  sayHello(@http.request() req: Request) {}
}

@http.response()

Decorate a param of a controller method to get the response object.

import { http } from 'xloop/decorators';

export class SomeController {
  sayHello(@http.response() res: Response) {}
}

@http.header(string, string)

Decorate a controller method to specify a custom response header.

import { http } from 'xloop/decorators';

export class SomeController {
  @http.header('Cache-Control', 'no-cache')
  sayHello() {}
}

You can apply multiple header decorators to the method for more custom headers:

import { http } from 'xloop/decorators';

export class SomeController {
  @http.header('Cache-Control', 'no-cache')
  @http.header('X-Hello', 'Hello World')
  sayHello() {}
}

@http.status(number)

Decorate a controller method to change the status code of the response statically.

import { http } from 'xloop/decorators';

export class SomeController {
  @http.status(202)
  sayHello() {}
}

@http.context()

Decorate a param of a controller method to get the context object.

import { http } from 'xloop/decorators';

export class SomeController {
  sayHello(@http.context() ctx: Context) {}
}

Custom Error Codes

Loopback v4 defines a few error codes and we can set up our own codes:

const ENTITY_DUPLICATED = 'ENTITY_DUPLICATED';
class EntityDuplicatedError extends Error {
  ...
  code = ENTITY_DUPLICATED;
}

class Application extends RestApplication {
  constructor(...) {
    ...
    this.configure(RestBindings.SequenceActions.REJECT).to(
      {
        [ENTITY_DUPLICATED]: 422,
      },
    );
  }
}