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

見綸 陳
見綸 陳
6,333 Points
Posted by 見綸 陳
見綸 陳
6,333 Points

Return function value in prototype

I try to console.log dice.roll and dice10.roll, but the outcome doesn't return the value. Should it be return a number value?

I open the chrome dev tool. The console.log outcome is a function, as following

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

Here is my code!

function Dice(sides) {
  this.sides = sides;
}
Dice.prototype.roll = function() {
  var randomNumber = Math.floor(Math.random() * this.sides) + 1;
  return randomNumber;
}
var dice = new Dice(6);
var dice10 = new Dice(10);
console.log(dice.roll === dice10.roll);
console.log(dice.roll);
console.log(dice10.roll);

1 Answer

webdesignertroy
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webdesignertroy
Front End Web Development Techdegree Graduate 14,718 Points
webdesignertroy
.a{fill-rule:evenodd;}techdegree seal-36
webdesignertroy
Front End Web Development Techdegree Graduate 14,718 Points

You need to invoke your functions or else they are just returning an echo of your script. This is what I did:

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

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

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

console.log(dice.roll() === dice10.roll());  //<===== Notice the parentheses after each function
console.log(dice.roll());  //<===== Notice the parentheses after the function
console.log(dice10.roll());  //<===== Notice the parentheses after the function