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JavaScript Design Patterns for Coding Interviews

Challenge: Solution Review

This lesson will explain the solution to the problem from the last coding challenge.

We'll cover the following...

Solution #

Node.js
class SuperHero {
  constructor(name,power) {
    this.name = name
    this.power = power
  }
}
function SuperHeroWithSword(superhero){
    superhero.sword = true
    superhero.hasSword= function(){
    return `${this.name}'s power is ${this.power}, and he also has a sword now.`
  }
  return superhero;
} 
function SuperHeroWithSuperSpeed(superhero) {
    superhero.superSpeed = true
    superhero.hasSuperSpeed= function(){
    return `${this.name}'s power is ${this.power}, and he also has the super speed now.`
  }
  return superhero;
}
function SuperHeroWithSpeedandSword(superhero){
    superhero.speedAndSword = true
  
  superhero.hasSpeedAndSword = function(){
    return `${this.name}'s power is ${this.power}, and he also has both super speed and a sword now.`
  }
  return superhero;
}
var superhero1 = new SuperHero("Fire Man", "Fire")
SuperHeroWithSword(superhero1)
console.log(superhero1.hasSword())
SuperHeroWithSuperSpeed(superhero1)
console.log(superhero1.hasSuperSpeed())
var superhero2 = new SuperHero("Ice Man", "Ice")
SuperHeroWithSpeedandSword(superhero2)
console.log(superhero2.hasSpeedAndSword())

Explanation

Let’s start by going through the original code, so we can understand how to modify it.

Node.js
class SuperHero {
  constructor(name,power) {
    this.name = name
    this.power = power
  }
}
class SuperHeroWithSword extends SuperHero{
  constructor(name,power){
    super(name,power)
    this.sword = true
  }
  hasSword(){
    return `${this.name}'s power is ${this.power}, and he also has a sword now.`
  }
}
class SuperHeroWithSuperSpeed extends SuperHero{
  constructor(name,power){
    super(name,power)
    this.superSpeed = true
  }
  hasSuperSpeed(){
    return `${this.name}'s power is ${this.power}, and he also has the super speed now.`
  }
}
class SuperHeroWithSpeedandSword extends SuperHero{
  constructor(name,power){
    super(name,power)
    this.speedAndSword = true
  }
  hasSpeedAndSword(){
    return `${this.name}'s power is ${this.power}, and he also has both super speed and a sword now.`
  }
}
var superhero1 = new SuperHeroWithSword("Fire Man", "Fire")
console.log(superhero1.hasSword())
var superhero2 = new SuperHeroWithSuperSpeed("Fire Man", "Fire")
console.log(superhero2.hasSuperSpeed())
var superhero3 = new SuperHeroWithSpeedandSword("Ice Man", "Ice")
console.log(superhero3.hasSpeedAndSword())

You can see that the original code implements inheritance to create a customized character. It has a SuperHero class that looks like:

class SuperHero {
  constructor(name,power) {
    this.name = name
    this.power = power
  }
}

Each SuperHero instance will have a name and power. Next, there are three child classes, all of which extend the functionality of the SuperHero class like so:

 ...