The Node Dependency Injection component allows you to standardize and centralize the way objects are constructed in your application.

npm install --save node-dependency-injection

Imagine you have a Mailer class like this:

// services/Mailer.js

export default class Mailer {
  /**
   * @param {ExampleService} exampleService
   */
  constructor(exampleService) {
    this._exampleService = exampleService;
  }

  ...
}

You can register this in the container as a service:

import {ContainerBuilder} from 'node-dependency-injection'
import Mailer from './services/Mailer'
import ExampleService from './services/ExampleService'

let container = new ContainerBuilder()

container
  .register('service.example', ExampleService)

container
  .register('service.mailer', Mailer)
  .addArgument('service.example')

And get services from your container

const mailer = container.get('service.mailer')

You can also use configuration files to improve your service configuration

# /path/to/file.yml
services:
  service.example:
    class: 'services/ExampleService'

  service.mailer:
    class: 'services/Mailer'
    arguments: ['@service.example']

import {ContainerBuilder, YamlFileLoader} from 'node-dependency-injection'

let container = new ContainerBuilder()
let loader = new YamlFileLoader(container)
loader.load('/path/to/file.yml')

And get services from your container easily

...
const mailer = container.get('service.mailer')

• Configuration files with JS, YAML or JSON.
• Multiple configuration files
• Custom relative service directory
• Compiling container
  • Custom compiler pass
  • Change definition behaviour
• Using a factory to create services
• Nullable Dependencies
• Public or private services
• Service Aliasing
• Service Tagging
• Parameters Injection
• Lazy Services
• Deprecate Services
• Decorate Services
• Synthetic Services
• Non Shared Services
• Parent and Abstract Services
• Custom Logger
• Container as Service

Please read full documentation

If you are using expressJS and you like Node Dependency Injection Framework then I strongly recommend you to use the node-dependency-injection-express-middleware package. That gives you the possibility to retrieve the container from the request.

npm install --save node-dependency-injection-express-middleware

import NDIMiddleware from 'node-dependency-injection-express-middleware'
import express from 'express'

const app = express()

const options = {serviceFilePath: 'some/path/to/config.yml'}
app.use(new NDIMiddleware(options).middleware())

Express Middleware Documentation

If you are using typescript and you like Node Dependency Injection Framework then typing are now provided at node-dependency-injection so you do not have to create custom typing anymore.

npm install --save node-dependency-injection

import { ContainerBuilder } from 'node-dependency-injection'
import MongoClient from './services/MongoClient'
import { Env } from './EnvType'

export async function boot(container = new ContainerBuilder(), env: Env) {
    container.register('Service.MongoClient', MongoClient).addArgument({
        host: env.HOST,
        port: env.PORT,
    })
}

• Documentation
• Collaboration and pull requests
• Milestones
• Twitter @zazoomauro
• Changelog