'This'.md

Challenge Name: Introducing "This"

Challenge

Make code more reusable with “this”.

Challenge Description

We are going to look at our sayName method from the previous example

  sayName: function() {return "The name of this duck is " + duck.name + "."}

Notice how we are referencing our object's name, duck, when accessing its name property. While this is a totally valid way to access our object's property, there is a bit of a pitfall here.

What if the name of our object changes? What if, instead of a duck, it's a mallard now? Well, we would have to change duck.name to mallard.name. In this small example, that's fine, but what happens when we have an object that makes many references to its properties throughout its methods? Now the process gets much more complex!

There's a way to avoid that all. Introducing...this:

var duck = {
  name: "Aflac",
  numLegs: 2,
  sayName: function() {return "The name of this duck is " + this.name + "."}
} 

This is a very robust topic that would be a great idea to research more deeply. For now, understand that this, in the current context, refers to the object that our method is associated with-duck.

Now, if we changed our object's name to mallard, we don't have to find all our references to duck in our code. We've made our code highly reusable and easy to read.

Instructions

Refactor the code below so that the Dog object follows the same code style as the Duck object.

Challenge Seed

var dog = {
  name: “Spot”,
  numLegs: 4,
  sayLegs: function() {return "This dog has " + dog.numLegs + " legs."}
}

dog.sayLegs();

Challenge Tests

Test to see if dog.sayLegs() still returns the desired string. assert(dog.sayLegs() === “This dog has 4 legs.”), ‘message: dog.sayLegs() should return the desired string.’

Challenge Solution

var dog = {
  name: “Spot”,
  numLegs: 4,
  sayLegs: function() {return "This dog has " + this.numLegs + " legs."}
}

dog.sayLegs();