arrow-express

Arrow Express

Aim of this library is to make express applications bootstrapping easy and fast with zero configuration.

Main principles:

• Avoid adding complex configuration, lib will work out of the box
• Focus on clean functional programming, avoid usage of complex additional configuration ideas like decorators etc.
• Flexibility and ease of use

Example code

Application({
  port: 8080,
  app: Express().use(BodyParser())
}).registerController(
  Controller()
    .prefix('users')
    .registerRoutes(
      Route()
        .method('get')
        .handler(
          (req) => getUser(req.body.id)
        ),
      Route()
        .method('post')
        .path('create')
        .handler(
          (req) => createUser(req.body.id)
        )
    ),
).start();
/**
 * Created paths in express application:
 * GET:/users
 * POST:/users/create
 * 
 * For full example application check out example folder.
 */

Docs

Application

Point of start for every application. Here you can configure Express application or port used by your application.

Application Methods

• registerController - register controller in application.
• start - starts application, register controllers routes in express app and connect to configured port

Example usage of Application

Application({
  port: 8080,
  app: Express().use(Compression()).use(BodyParser()),
})
.start();

Controller

Controller is used to manage group of routes.

Example usage of Controller

/**
 * We advise to split each controller.
 */
function LoginController () {
  return Controller()
    .prefix('login');
}

function UserController () {
  return Controller()
    .prefix('user');
}

Application({port: 8080})
  .registerController(
    LoginController(),
    UserController(),
  )
  .start();

Controller Methods

• prefix - register controller prefix which will be used by all routes
• registerRoute - register route in controller

Route

Route is used to manage route handling.

Example usage of route

/**
 * Similar to controllers we advise to split every handler / route into separate file.
 */
function CheckToken (): UserId {
  // here we check if user is logged by proper token
  return userId;
}

function getUserRoute() {
  return Route()
    .method('get')
    .path('myself')
    .contextGuard(CheckToken)
    .handler(async (req: Express.Request, res: Express.Response, userId: UserId) => {
      // here we can get user using UserId received from guard
      return user;
    });
}

function LoginController () {
  return Controller()
    .prefix('user')
    .registerRoutes(
      getUserRoute()
  );
}

Application({port: 8080})
  .registerController(
    LoginController(),
  )
  .start();

// Registered path will be: '/user/myself'

Route Methods

• method - register method used for route
• path - register path of route alongside with prefix it is used to create full path
• handler - set request handler, here you can handle request
• contextGuard - used to add pre-checks or side operations for request if guard throw error, handler is not called

Route handler

Route handler receive 3 arguments:

• request - which is Express.Request for path
• response - which is Express.Response
• context - which is optional context returned by last guard

Route handler can return Promise or Object which will be send back with response code 200 or void.

Route handler can also send response itself using res then library won't try to send back result pf handler.

Route Guard

Route Guard receive 2 arguments:

• request - which is Express.Request for path
• response - which is Express.Response

Route Guard can return context which can be used in handler later.