DI Service

Really simple dependency injection solution for JavaScript

Features

• Implements DI pattern
• Do not impose any system architecture, may be introduced to any JavaScript project (FE and BE both)
• Pure JavaScript implementation (+ TypeScript declaration file)
• Zero dependencies
• ES Module and CommonJS hybrid module

Example

Declare any class

class Settings {
    dbServer = process.ENV.DB_SERVER;
    dbUser = process.ENV.DB_USER;
    dbPassword = process.ENV.DB_PASSWORD; // don't do like this
}

module.exports = { Settings };

Use the class as a dependency

const { Settings } = require('./settings');
const { SERVICE_REQUIRE } = require('di-service');

class DBConnection {
    
    static [SERVICE_REQUIRE] = [Settings];
    
    constructor(settings) {        
        // settings -> instance of the Settings class
        this.settings = settings;
    }
}

module.exports = { DBConnection };

Get service instance

const { DIService } = require('di-service');
const { DBConnection } = require('./db-connection');

const services = new DIService();
const connection1 = await services.getInstance(DBConnection);
const connection2 = await services.getInstance(DBConnection);
console.log(connection1 === connection2); // -> true
console.log(connection1.settings === connection2.settings); // -> true
console.log(connection1.settings.constructor.name); // -> Settings

Used by