Programming Concepts — Design Patterns

Design patterns are common solutions to recurring software design problems. Examples include Singleton, Observer, and Factory patterns.

// Singleton pattern example
class Singleton {
  constructor() {
    if (!Singleton.instance) {
      Singleton.instance = this;
    }
    return Singleton.instance;
  }
}
const instance1 = new Singleton();
const instance2 = new Singleton();
console.log(instance1 === instance2); // Output: true