@zirion/ioc

An IoC (Inversion of Control) implementation using dependency injection for Node.js.

Table of Contents

• Installation
• Features
• Usage
• Examples
• Contributing

Installation

You can install the package using npm or yarn:

npm install @zirion/ioc

or

yarn add @zirion/ioc

Features

• Lightweight and easy to use
• Supports constructor method injection
• Singleton and request lifetimes
• Dependency resolution
• Contexts for request-scoped providers
• Code is free from dependencies

Roadmap:

• More ways to inject - property, method
• More lifetimes - transient
• Circular dependencies check
• Isolated dependency groups
• Lazy initialization configuration (Currently all registered providers are lazy initable)
• More lifecycle hooks
• Decorators Stage-3 support
• Tests
• In-code documentation
• More code examples in repository

Usage

Basic Usage

Firstly we have container constant exported from the package. It our first point where starting on

import container from '@zirion/ioc/container';

container.add('my_key', {
  value: {
    data: 'My first injectable object!',
  },
}).finalize();

const obj = container.get('my_key');

// My first injectable object!
console.log(obj.data);

Let's take a look to how to use a thing in the simpliest way:

import container from '@zirion/ioc/container'

class ThemService {
  // ...
}

class MyService {
  constructor(themService: ThemService) {
    // Yaay! We got injected
  }

  // ...
}

// There added new services into main container
// Note: By default providers are added as singleton
container
  // Providers order is important!
  .add(ThemService)
  .add(MyService, { inject: [ThemService] })
  // End builder with calling this function to run our hooks
  .finalize()

// Now we can use our instance. It's lazy - only be initied when we got them
const myService = container.get(MyService)

Examples

Context scoped provider case:

import container from '@zirion/ioc/container'
import { InjectScope } from '@zirion/ioc';

class MyService {
  constructor(context) {
    // In request-scoped providers context got auto-injected as latest parameter in constructor
  }
}

container
  .add(MyService, { scope: InjectScope.REQUEST })
  .finalize()

const myContext = {
  reqId: 1,
  foo: 'bar',
}

// To use request-scoped instance it's required to pass a context in second argument
const myService = container.get(MyService, myContext);

Also, there is some rule:

• Request-scoped instance CAN'T be injected into singletone-scoped one

Contributing

Contributions are welcome! Please read the contribution guidelines first.

License

This project is licensed under the MIT License.