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JavaScript Object-Oriented JavaScript (2015) Introduction to Methods Understanding this

Posted by Rita Bradley
Rita Bradley
Courses Plus Student 4,894 Points

Arrow function returns NaN to console

I was wondering why when I write this code the exact same way but using an arrow function instead, instead of returning a random number, I get NaN?

var dice = {
  sides: 6,
  roll: () => {
    var randomNumber = Math.floor(Math.random() * this.sides) + 1;
    console.log(randomNumber);
  }
};

1 Answer

Steven Parker
Steven Parker
229,771 Points
Steven Parker
Steven Parker
229,771 Points

Arrow functions don't use this like conventional functions do.

For this reason, they are not well suited for method functions. For more details see the MDN page on Arrow Functions.

Rita Bradley
Rita Bradley
Courses Plus Student 4,894 Points

Ah. Well, you learn something new every day! Thanks Steven!