simpleEnemyFactory.ts

export class SimpleEnemyFactory {

  public create(enemyType: string): Enemy {
    switch (enemyType) {
      case "bobbie":
        return new Bobbie();

      case "wallace":
        return new Wallace();

      case "kanye":
        return new Kanye();

      default:
        // Oops, no Enemy of this type!
        break;
    }
  }
}