Application Instance (exis)

The exis() function is the primary entry point for configuring and booting your ExisJS application. It defines your core configuration, middleware, plugins, and lifecycle hooks.

It returns a configured App instance that the CLI or deployment platform will automatically discover and run. The framework's auto-discovery mechanism effortlessly handles both Functional and Class-Based (OOP) routes inside your src/http directory.

Usage

ExisJS supports both Functional and Class-Based (OOP) paradigms for configuring your application entry point.

1. Functional Setup

import { exis } from 'exisjs'import { cors } from 'exisjs/middleware'
export default exis({  port: 3000,  helmet: true,  cors: {    origin: '*',  },  middlewares: [    cors()  ],  async onStart(app) {    app.log.info("Server is starting up!")  }})

2. Class-Based Setup (OOP)

If you prefer an Object-Oriented approach, you can define your application entry point using the @Server() decorator.

import { Server } from 'exisjs/decorators'import type { App } from 'exisjs'
@Server({  plugins: [    // You can register plugins or configuration directly in the decorator options  ]})export default class RootServer {  async onStart(app: App) {    app.log.info("Server is starting up!")  }    async onClose(app: App) {    app.log.info("Server is shutting down!")  }}

Configuration Options

The exis() function takes an ExisConfig object.

port

• Type: number
• Default: 3000 (or process.env.PORT)
• The port the server will listen on during development or manual instantiation.

host

• Type: string
• Default: '0.0.0.0' (or process.env.HOST)
• The host the server will bind to.

env

• Type: 'development' | 'production' | 'test'
• Default: Auto-detected via NODE_ENV.
• The current environment of the application.

logger

• Type: boolean | LoggerConfig
• Default: true
• Toggles the built-in Pino logger. You can pass a custom configuration object to set the log level, redact sensitive fields, or output JSON.

helmet

• Type: boolean
• Default: true
• Automatically applies security headers to every response. Set to false to disable.

cors

• Type: boolean | CorsConfig
• Default: false
• Automatically injects CORS headers into the request pipeline. You can pass a configuration object to specify allowed origins, methods, and credentials.

compression

• Type: boolean
• Default: true (if applicable)
• Automatically compresses HTTP responses (gzip/brotli).

middlewares

• Type: Handler[]
• Default: []
• An array of global middleware functions that will run on every single request.

plugins

• Type: ExisPlugin[]
• Default: []
• An array of ExisJS plugins to register.

Lifecycle Hooks

You can define async hooks that execute at specific stages of the application's lifecycle.

onStart(app: App)

Fired after configuration is loaded but before the server starts accepting connections. This is the ideal place to connect to databases, initialize singletons, or run startup migrations.

onClose(app: App)

Fired when the server receives a shutdown signal (e.g., SIGINT, SIGTERM). Use this to gracefully close database connections, flush analytics events, or tear down background workers.