Builder Design Pattern

The Builder Design Pattern is particularly useful when an object's construction process involves multiple steps or configurations. It provides a clear and fluent interface for constructing objects, allowing clients to specify different configurations without needing to understand the complex construction logic.

class Pizza {
  constructor() {
    this.crust = "";
    this.sauce = "";
    this.toppings = [];
  }

  addCrust(crust) {
    this.crust = crust;
  }

  addSauce(sauce) {
    this.sauce = sauce;
  }

  addTopping(topping) {
    this.toppings.push(topping);
  }

  describe() {
    console.log(`Pizza with ${this.crust} crust, ${this.sauce} sauce, and toppings: ${this.toppings.join(", ")}.`);
  }
}

// Builder class
class PizzaBuilder {
  constructor() {
    this.pizza = new Pizza();
  }

  addCrust(crust) {
    this.pizza.addCrust(crust);
    return this;
  }

  addSauce(sauce) {
    this.pizza.addSauce(sauce);
    return this;
  }

  addTopping(topping) {
    this.pizza.addTopping(topping);
    return this;
  }

  build() {
    return this.pizza;
  }
}

// Usage
const pizza = new PizzaBuilder()
  .addCrust("thin")
  .addSauce("tomato")
  .addTopping("cheese")
  .addTopping("mushrooms")
  .build();

pizza.describe();

PizzaBuilder serves as the builder class, providing methods for adding crust, sauce, and toppings to the pizza.

The Builder Design Pattern offers a flexible and fluent way to construct complex objects with multiple configurations. By encapsulating the construction logic within a builder class, developers can create objects with different representations while keeping the client code clean and easy to understand.