ExisJS

Decorators

ExisJS provides a rich ecosystem of standard ES6 decorators for developers who prefer the Object-Oriented Programming (OOP) paradigm (heavily inspired by NestJS).

Because ExisJS does not rely on heavy reflection libraries like reflect-metadata, these decorators are incredibly fast and memory-efficient.

All decorators can be imported directly from exisjs/decorators.

1. Servers & Gateways

ExisJS allows you to configure your root application and directory-scoped gateways using decorators, completely replacing the need for functional exis() and defineGateway() wrappers if you prefer OOP.

@Server(config)

Used exclusively in your src/http/server.ts file to bootstrap the application.

src/http/server.ts
import { Server } from 'exisjs/decorators'import { metricsPlugin } from './plugins/metrics'import type { App } from 'exisjs'
@Server({  plugins: [metricsPlugin],  providers: [['Logger', { useValue: console }]]})export default class RootServer {  async onStart(app: App) {    console.log('Server started!')  }}

@Gateway(config)

Used inside any folder (e.g. src/http/admin/gateway.ts) to act as a gatekeeper for all routes within that directory and its subdirectories.

src/http/admin/gateway.ts
import { Gateway } from 'exisjs/decorators'import { requireAuth } from '../../middleware/auth'
@Gateway({  middleware: [requireAuth],  cors: { origin: 'https://admin.com' },  timeout: 10000,  metadata: { openapi: { tags: ['Admin'] } }})export default class AdminGateway {}

1. Controllers & Routing

To map a class to a route prefix, use the @Controller() decorator. You can then use HTTP Method decorators to map class methods to specific endpoints.

src/http/users/route.ts
import { Controller, Get, Post, Put, Delete } from 'exisjs/decorators'
@Controller('/users')export default class UsersController {    @Get('/')  async listUsers() {    return { users: [] }  }
  @Post('/create')  async createUser() {    return { success: true }  }    @Delete('/:id')  async deleteUser() {}}

Available Method Decorators

  • @Get(path?, schema?)
  • @Post(path?, schema?)
  • @Put(path?, schema?)
  • @Patch(path?, schema?)
  • @Delete(path?, schema?)
  • @Options(path?, schema?)
  • @Head(path?, schema?)
  • @All(path?, schema?)
  • @Ws(path?, schema?) (For WebSockets)
  • @Sse(path?, schema?) (For Server-Sent Events)

2. Request Parameters

Instead of manually digging through the req object, ExisJS allows you to cleanly inject request properties directly into your method parameters.

src/http/users/route.ts
import { Controller, Post, Body, Param, Headers, Req, Res } from 'exisjs/decorators'
@Controller('/users')export default class UsersController {    @Post('/:id')  async update(    @Param('id') id: string,    @Body() payload: any,    @Headers('authorization') token: string,    @Req() req: any,    @Res() res: any  ) {    return { success: true, id, payload }  }}

Available Parameter Decorators

  • @Body(key?) - Extracts req.body or a specific key.
  • @Param(key?) - Extracts req.params or a specific key.
  • @Query(key?) - Extracts req.query or a specific key.
  • @Headers(key?) - Extracts req.headers or a specific key.
  • @Req() - Injects the underlying ExisRequest object.
  • @Res({ passthrough?: boolean }) - Injects the underlying ExisResponse object.
  • @Ip() - Extracts the client IP address.
  • @Next() - Injects the next() function for middleware bypass.
  • @Session() - Injects req.session (if a session plugin is active).
  • @Socket() - Injects the ExisWebSocket (only valid in @Ws routes).
  • @Stream() - Injects the ExisSSE stream (only valid in @Sse routes).
  • @UploadedFile() / @UploadedFiles() - Automatically extracts multipart form-data files!

3. Middleware & Lifecycles

You can bind Middleware, Guards, Exception Filters, and Interceptors directly to your Controllers or individual methods using decorators!

src/http/admin/route.ts
import { Controller, Get, Use, UseGuards, UseFilters } from 'exisjs/decorators'import { requireAuth } from '../../middleware/auth'import { RoleGuard } from '../../guards/role'import { AdminErrorFilter } from '../../filters/admin'
@Controller('/admin')@Use(requireAuth) // Applies to the entire class@UseFilters(AdminErrorFilter) // Applies to the entire classexport default class AdminController {    @Get('/dashboard')  @UseGuards(RoleGuard) // Applies ONLY to this method  async getDashboard() {    return { secret: 'data' }  }}

Available Lifecycle Decorators

  • @Use(...middlewares) - Binds standard Express-style middleware.
  • @UseGuards(...guards) - Binds ExisJS authorization Guards.
  • @UseInterceptors(...interceptors) - Binds response Interceptors.
  • @UseFilters(...filters) - Binds Exception Filters.

4. Response Modifiers

Sometimes you need to modify the HTTP Response (like changing the status code or adding a header) without injecting the raw @Res() object.

src/http/api/route.ts
import { Controller, Post, HttpCode, Header, Redirect } from 'exisjs/decorators'
@Controller('/api')export default class ApiController {    @Post('/create')  @HttpCode(201) // Forces the response status to 201 Created  @Header('X-Custom-Version', '2.0') // Appends a custom header  async create() {    return { success: true }  }    @Get('/legacy')  @Redirect('/new-api', 301) // Automatically redirects the client!  async legacy() {}}

Available Response Decorators

  • @HttpCode(code: number)
  • @Header(name: string, value: string)
  • @Redirect(url: string, statusCode?: number)
  • @Hosts(...hosts: string[]) - Restricts a route/controller to a specific Host header (e.g. api.example.com).

5. Dependency Injection

To mark a class as a service that can be injected into your controllers, use the @Injectable() decorator.

src/services/db.ts
import { Injectable } from 'exisjs/decorators'
@Injectable({ scope: 'singleton' })export class DatabaseService {  async findUser() { ... }}
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