johnnystefan/pattern-builder

Skill: Implement Builder Pattern

Purpose

Constructs complex objects step by step. It allows producing different types and representations of an object using the same construction code.

Procedural Instructions

1. Identify Multi-step Creation: Look for "Telescoping Constructors" (too many parameters).
2. Create Builder Interface: List all possible construction steps.
3. Implement Concrete Builders: Define how each step is executed for a specific representation.
4. Director (Optional): Define the order of steps for common configurations.

TypeScript Example

class Car {
  public seats: number = 0;
  public engine: string = '';
  public gps: boolean = false;
}

interface Builder {
  reset(): void;
  setSeats(n: number): void;
  setEngine(e: string): void;
  setGPS(g: boolean): void;
}

class CarBuilder implements Builder {
  private car: Car = new Car();
  reset() {
    this.car = new Car();
  }
  setSeats(n: number) {
    this.car.seats = n;
  }
  setEngine(e: string) {
    this.car.engine = e;
  }
  setGPS(g: boolean) {
    this.car.gps = g;
  }
  getProduct(): Car {
    return this.car;
  }
}

Payoff

• Control: Finer control over the construction process.
• Reusability: Same construction code can build different products.