alpha-dic

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('[e-mail]', 'limits-exceeded', {})
    })

• Simple usage rules
• Defining services
• Decorators
• Annotations
• Middlewares
• Hierarchical container
• Injecting configuration values
• Hooks - @OnActivation, onActivation
• Deprecating services
• Autowiring
• Big projects tips
• Example