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JavaScript JavaScript Foundations Objects Prototypes

Posted by Steve Muthig
Steve Muthig
4,225 Points

JavaScript Code Challenge ???

Modify the Car's Prototype to have "wheels" set to 4

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

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


  }

  Car.prototype = carPrototype; {
wheels = new Car ("4");
  }
</script>

</body> </html> '''

6 Answers

Russell Wood
Russell Wood
12,088 Points

I believe that you just need to add a wheels property to the carPrototype and set a default value of 4 like so:

''' ... decreaseGear: function() { this.currentGear--; }, wheels: 4 }'''

Mike Healy
Mike Healy
2,451 Points

I think that'd give a syntax error. You're in the method scope, so this.wheels = 4 is probably what you meant, but using the decreaseGear function isn't a good place for that anyway. That method may never be called. The prototype still needs a default number of wheels.

Russell Wood
Russell Wood
12,088 Points
Russell Wood
Russell Wood
12,088 Points

It doesn't matter. You can declare a property after a method (in this case "decreaseGear") because in the end, they are both properties. Just be sure to put a "," after the closing "}" of the function to continue with the property declaration. However, what you have works just fine. Sometimes order is a matter of preference. Of course, I'm on this site because I'm not an expert either, just speaking from experience.

Mike Healy
Mike Healy
2,451 Points

Ah, I misread your code. It looked like wheels: 4 was inside the decreaseGear() method at first glance. That will work, but probably a lot less clear than grouping with the other properties at the top of the prototype.

Mike Healy
Mike Healy
2,451 Points
Mike Healy
Mike Healy
2,451 Points

How about this? Passing 4 to the constructor will set that as the Model property.

  var carPrototype = {
    model: "generic",
    wheels: 4,
    currentGear: 0,

   ....
Russell Wood
Russell Wood
12,088 Points
Russell Wood
Russell Wood
12,088 Points

Yep, I'm not quite clear on how I can make it look better because I've tried the markdown syntax and it generally looks as confusing either way.

Mike Healy
Mike Healy
2,451 Points
Mike Healy
Mike Healy
2,451 Points

If you wanted to get the syntax highlighting use backticks (beside the 1) not single quotes You can specify a language after the opening backticks

var muchSyntax = true;

$highlight = 'wow';
Russell Wood
Russell Wood
12,088 Points

Awesome! I've been using the wrong ones this entire time. Look at me I'm on top of the : var hello = "Hello World!!!"

Mike Healy
Mike Healy
2,451 Points
Mike Healy
Mike Healy
2,451 Points

Btw, they have to start after a blank line

Russell Wood
Russell Wood
12,088 Points

So close, but thanks for the tips.