singletone-design-pattern.js

//  The 4 Creational Design Patterns In Node.js
// https://daily.dev/blog/the-4-creational-design-patterns-in-node-js-you-should-know

// The Singletone Pattern

class DatabaseConnection {
  constructor() {
    this.databaseConnection = 'dummytext';
  }

  getNewDBConnection() {
    return this.databaseConnection;
  }
}

class Singleton {
  constructor() {
    throw new Error('Use the getInstance() method on the Singleton object!');
  }

  getInstance() {
    if (!Singleton.instance) {
      Singleton.instance = new DatabaseConnection();
    }

    return Singleton.instance;
  }
}

module.exports = Singleton;

// or 

class DatabaseConnection {
  constructor() {
    this.databaseConnection = 'dummytext';
  }

  getNewDBConnection() {
    return this.databaseConnection;
  }
}

module.exports = new DatabaseConnection();