Deepkit App

@deepkit/app

Command line interface (CLI) framework for TypeScript with service container, module system, hooks, and easy to define commands.

Features

Commands

Easy to define commands with arguments and flags based on runtime types.

Service Container

Full fledged dependency injection for classes and even functions.

Event System

Powerful event system with hooks for your application.

Modules

Highly customizable module system with hooks and inheritance.

Configuration

Configuration loader (env, dotenv, json) and option injection.

Logger

Logger with support for colors and multiple transports.

Commands

Write CLI commands with class methods or simple async functions.

All CLI arguments and flags are extracted out of the function signature and are automatically deserialized and validated based on its types.

import { App } from '@deepkit/app';

class MyCommand {
    async execute(name: string = 'body') {
        console.log('Hello', name);
    }
}

const app = new App({
    controllers: [MyCommand],
});
app.run();

import { App } from '@deepkit/app';

const app = new App();

app.command('test', async (name: string = 'body') => {
    console.log('Hello', name);
});

app.run();

Arguments and Flags

Arguments and flags are automatically deserialized based on its types, validated and can be provided with additional constraints.

import { Flag, App } from '@deepkit/app';

const app = new App();

app.command('user:find', async (
    name: string & Flag = '',
    age: number & Flag = '',
    active: boolean & Flag = false,
) => {
    // name is a string, age a number, active a boolean
});

// ts-node app.ts user:find --name Peter --age 20 --active

Dependency Injection

The service container allows you to inject dependencies into your commands, controllers, and hooks, without any boilerplate code.

import { App } from '@deepkit/app';

class MyDatabase extends Database {} //your database class

const app = new App({
    providers: [MyDatabase],
});

app.command('user:find', async (
    name: string & Flag = '',
    db: MyDatabase, // automatically injected
) => {
    const users = await db.query(User).filter({name}).find();
    console.log(users);
});

app.run();

Configuration

Define your configuration as class including validation constraint and load it automatically from environment variables, dotfiles, or JSON files.

Configuration options can be injected into your commands, controllers, and hooks.

import { App } from '@deepkit/app';

class Config {
    domain: string = 'localhost';
}

const app = new App({
    config: Config,
    providers: [MyDatabase],
});

app.command('url', async (
    name: string & Flag = '',
    db: MyDatabase, // automatically injected
    domain: Config['domain'], // automatically injected
) => {
    const user = await db.query(User).filter({ name }).findOne();
    console.log('url', `https://${domain}/user/${user.username}`);
});

app.run();

Modules

Powerful module system with hooks and inheritance that allows to easily extend your application.

Modules can bring their own providers, controllers, event listeners, and configuration.

import { App, AppModule } from '@deepkit/app';

export function myModule(options: {}) {
    return (module: AppModule) => {
        module.addProvider(MyDatabase);
        module.addController(MyController);
        module.addListener();

        //make MyDatabase available for parent modules
        module.addExport(MyDatabase);
    };
}

const app = new App({
    config: Config,
    imports: [
        myModule({}),
    ]
});

app.command('url', async (
    name: string & Flag = '',
    db: MyDatabase, // automatically injected from module
) => {
    //...
});

app.run();

Event System

The event system allows you to hook into the application lifecycle and react to events.

All listeners have full access to the service container and can receive dependencies allowing to write nicely decoupled code.

import { App, onAppExecute } from '@deepkit/app';

const app = new App();

app.listen(onAppExecute, async (event, logger: Logger) => {
    logger.log('app started');
});

app.run();

Deepkit App

Features

Commands

Arguments and Flags

Dependency Injection

Configuration

Modules

Event System

Questions & Answers

Examples