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JavaScript Object-Oriented JavaScript (2015) Constructor Functions and Prototypes Methods with Prototypes

Kyle Vassella
Kyle Vassella
9,033 Points
Posted by Kyle Vassella
Kyle Vassella
9,033 Points

sides is not defined?

For some reason I my code is returning with the error: dice.js:6 Uncaught ReferenceError: sides is not definedDice.roll @ dice.js:6button.onclick @ ui.js:9

My code, at least on the dice.js, is the exact same as Chalkley's. Can anyone spot what I did wrong? Perhaps the issue lies on ui.js on line 9, as suggested above?

dice.js:

function Dice(sides) {
  this.sides = sides;
}

Dice.prototype.roll = function () {
    var randomNumber = Math.floor(Math.random() * sides) + 1;
    return randomNumber;
}

var dice = new Dice(6);
var dice10 = new Dice(10);

console.log(dice.roll === dice10.roll);

ui.js:

function printNumber(number) {
  var placeholder = document.getElementById("placeholder");
  placeholder.innerHTML = number;
}

var button = document.getElementById("button");

button.onclick = function() {
  var result = dice.roll();
  printNumber(result);
};

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! I believe this line is incorrect:

var randomNumber = Math.floor(Math.random() * sides) + 1;

Try this:

var randomNumber = Math.floor(Math.random() * this.sides) + 1;  //note the addition of "this"

Let me know if it helps! :sparkles:

Kyle Vassella
Kyle Vassella
9,033 Points
Kyle Vassella
Kyle Vassella
9,033 Points

Yup, that was it. Thanks for the second set of eyes, I was pretty frustrated at the time and somehow missed it. My code wasn't 'the exact same' as his after all. Awkward..