Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript Functions Arrow Functions Testing for Number Arguments

Yoan Halevy
seal-mask
.a{fill-rule:evenodd;}techdegree
Yoan Halevy
Full Stack JavaScript Techdegree Student 2,964 Points
Posted by Yoan Halevy
.a{fill-rule:evenodd;}techdegree
Yoan Halevy
Full Stack JavaScript Techdegree Student 2,964 Points

The code I have gives me back a value of "undefined". Can someone tell me why? 

const randomNumber = (lower, upper) => {
  Math.floor(Math.random() * (upper - lower + 1)) + lower;
  if (isNaN(lower) || isNaN(upper)) {
    throw Error ("You must select only numbers");
  }
}

// Call the function and pass it different values

console.log(randomNumber(1,5));
console.log(`${randomNumber(5,100)} is a random number between 5 and 100`);
console.log(randomNumber("six",987324));

1 Answer

Joseph Yhu
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,638 Points

You have to return the random number, like this:

const randomNumber = (lower, upper) => {
  if (isNaN(lower) || isNaN(upper)) {
    throw Error ("You must select only numbers");
  }
  return Math.floor(Math.random() * (upper - lower + 1)) + lower;
}