Alpha-dic NPM | npm.io

Alpha DIC

Flexible Dependency Injection Container with support for asynchronous service creation, annotations and middlewares.

Features:

Autowiring
Supports middlewares
Allows to define service as constructor, (async) factory or a value
Detects cycle dependencies
Prevents race condition for concurrent service requests
Supports annotations (and ability to search services by annotations)
Simple service definition via container methods or decorators

Installation

npm install alpha-dic

Example

import {createStandard} from 'alpha-dic';

const container = createStandard();
// if you're defining services via decorators
// preloadServiceModules(container, './path/to/service/modules/*')

container.definitionWithFactory('my-service', async () => {
        const connection = new DatabaseConnection();
        await connection.connect();
        return connection;
    });

container.get('my-service').then((connection) => {
    // connection has been established in factory
});

Example with dependencies and decorators

import {createStandard, reference, AutowiredService, Service, OnActivation} from 'alpha-dic';
import * as assert from 'assert';

const container = createStandard();

@AutowiredService('NotificationCenter')
class NotificationCenter {
    constructor(renderer: EmailRenderer, sender: EmailSender) {
        assert.ok(renderer instanceof EmailRenderer);
        // connection to SMTP was established in factory
        assert.ok(sender instanceof EmailSender);
    }
    async sendEmail(to, type, vars) {
        // render email
        // send it via sender
    }
}

@Service()
class EmailRenderer {
    
}

@Service()
@OnActivation(async (mailer) => {
    await mailer.connectToSMTP();
    return mailer;
})
class EmailSender {
    
}

container.get('NotificationCenter')
    .then((centre) => {
        return centre.sendEmail('admin@example.com', 'limits-exceeded', {})
    })