Ejemplo de DRY usando Javascript

DRY.js

// ----> Design Principles

// DRY

// 0
console.log("Don’t Repeat Yourself");

// 1
console.log("Encapsulate What Varies");

class Tax {
  calculteTax(){
      let tax = 0 //complex logic for tax;
      if(country == 'us'){
        tax = 10;
      } else {
        tax = 20;
      }

      this.calculateDb();
      this.calculateIP();
  }

  calculateDb(){
    // DB 
  }

  calculateIP(){
    // IP
  }
}

class Order {
  constructor(tax){
    this.tax = tax;
  }
  calculateTotal(){
    let subTotal = 10;
    // complex
    this.tax.calculteTax();
    return subTotal + tax;
  }

  
}

// 2
console.log("Encapsulation on a method level");

// 3
console.log("Encapsulation on a class level");