simple-decor

Purpose

Modern REST API frameworks allow simple syntax to register new routes and type check their data transfer object (DTO). In express, these processes can be verbose, but migrating to newer frameworks is not always an option.

The goal of simple-decor is to bring in uncomplicated decorator-based route registration and DTO type checking to Express projects. Additionally, it plans to include automatic OpenAPI documentation generation in upcoming versions.

Installation

Using npm:

$ npm i simple-decor

Usage

Register a POST company/:companyId/user and DTO type checking using controller decorators

import { Post, ParamIsInt, BodyIsClass } from "simple-decor";

class UserController {
  @Post("company/:companyId/user")
  @ParamIsInt("companyId")
  @BodyIsClass(PostUserBody)
  post(req: Request, res: Response) {
    const { email, name } = req.body as PostUserBody;

    //create user ...

    res.send(200);
  }
}

Add registered routes to express application

import { setup } from "simple-decor";

const app = express();
app.listen(3000);
setup(app);

Decorators

Route registration

| Decorator | Parameters | Description | | --------- | ------------- | ------------------------------ | | Get | path string | Registers a new GET route | | Patch | path string | Registers a new PATCH route | | Post | path string | Registers a new POSTroute | | Put | path string | Registers a new PUT route | | Delete | path string | Registers a new DELETE route |

Path param type checking

| Decorator | Parameters | Description | | ------------ | -------------------------- | ------------------------------------------------------------------------------------------------------------- | | ParamExists | name:string | Throws error if http request does not contains a path parameter with given name | | ParamIsInt | name:string | Throws error if http request does not contains a path parameter with given name that contains only digits | | ParamIsEmail | name:string | Throws error if http request does not contains a path parameter with given name that loosely matches an email | | ParamIsEnum | name:string, enum:enum | Throws error if http request does not contains a path parameter with given name that is in the given enum |

Query param type checking

| Decorator | Parameters | Description | | ------------ | -------------------------- | -------------------------------------------------------------------------------------------------------------- | | QueryExists | name:string | Throws error if http request does not contains a query parameter with given name | | QueryIsInt | name:string | Throws error if http request does not contains a query parameter with given name that contains only digits | | QueryIsEmail | name:string | Throws error if http request does not contains a query parameter with given name that loosely matches an email | | QueryIsEnum | name:string, enum:enum | Throws error if http request does not contains a query parameter with given name that is in the given enum |

Body type checking

| Decorator | Parameters | Description | | ----------- | ------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------- | | BodyIsClass | bodyClass: class | Throws error if http reqest body does not match the given class (class must be annotated with class-validator and class-transformer decorators |