Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

JavaScript JavaScript Foundations Objects Prototypes

sergio verdeza
PLUS
sergio verdeza
Courses Plus Student 10,765 Points

Modify the Car's prototype to have 'wheels' set to 4. Hello, having trouble with this question? Help.......

var carPrototype = { model: "generic", currentGear: 0,

increaseGear: function() {
  this.currentGear ++;
},
decreaseGear: function() {
  this.currentGear--;
} 

}

function Car (model) { this.model = model; }

Car.prototype = carPrototype;

Car.prototype.wheels = 4

index.html
<!DOCTYPE html>
<html lang="en">
  <head>
    <title> JavaScript Foundations: Objects</title>
    <style>
      html {
        background: #FAFAFA;
        font-family: sans-serif;
      }
    </style>
  </head>
  <body>
    <h1>JavaScript Foundations</h1>
    <h2>Objects: Prototypes</h2>
    <script>


      var carPrototype = {
        model: "generic",
        currentGear: 0,
        wheels: 4,
        increaseGear: function() {
          this.currentGear ++;
        },
        decreaseGear: function() {
          this.currentGear--;
        } 
      }

      function Car(model) { this.model = model; }

       Car.prototype.wheels = 4;




    </script>
  </body>
</html>

2 Answers

Madeleine Nyhagen
Madeleine Nyhagen
2,880 Points

I think you are just doing too much. I was successful using Car.prototype.wheels = 4; but did not add anything directly to the carPrototype variable. I believe my code looked like this:

var carPrototype = {
        model: "generic",
        currentGear: 0,
        increaseGear: function() {
          this.currentGear ++;
        },
        decreaseGear: function() {
          this.currentGear--;
        } 
      }

      function Car(model) {
        this.model = model;
      }

      Car.prototype = carPrototype;
      Car.prototype.wheels = 4;
chris slaats
chris slaats
5,996 Points

For this question you don't have to use Car.prototype.wheels = 4; because you have set the Car.prototype = carPrototype already. Then all the question is asking is of you is to change the Car's prototype which you have just set to carPorotypes variable wheels to 4 so it should look like this. Hope that helps

var carPrototype = {
        model: "generic",
        currentGear: 0,
        wheels: 4,
        increaseGear: function() {
          this.currentGear ++;
        },
        decreaseGear: function() {
          this.currentGear--;
        } 
      }

      function Car(model) {
        this.model = model;
      }

      Car.prototype = carPrototype;