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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Getting Information From a Function

Posted by Tom Lawrence
Tom Lawrence
8,685 Points

Return multiple things from a function

Hi, in this video (06:30) it says you cant return multiple things from a function but in the next video, we return multiple things from a function using the following:

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



function getArea(width , length, unit){

  var area = width * length;
  return area + " " + unit;
}

console.log(getArea(10,20, 'sq ft'));

Can someone clear up what it is you cant do with return as I must be missing something and watched it a couple of times now and a bit lost.

It was mentioned that "you can only return one thing, a string, a number a bool" so then I thought ok well maybe it can only return 1 type but that cant be right either as in the above return statement we have an int and a string! (as in the string " ", not the string held within the unit variable).

The only thing I can think is that 

return area + " " + unit;

actually isnt "returning multiple things" it is returning 1 thing which is concatenated, so multiple things joined together making "one thing" is that it?

Thanks

4 Answers

Dave McFarland
STAFF
Dave McFarland
Treehouse Teacher
Dave McFarland
Dave McFarland
Treehouse Teacher

Sorry for the confusion Tom. Dino Paškvan is correct. With this line of code

return area + " " + unit;

The stuff after return is evaluated before it is returned. So the area is added to a space which is added to the unit ('sq ft', for example) to create a SINGLE string, which is then returned. It's the same as

return '20 sq ft.';

JavaScript converts numeric values into strings when using the + operator with strings, so the number in the area variable is converted to its string version.

And yes, an array can hold multiple items in them -- that's why they're so useful. But when using the return statement with an array you're still just returning a single thing -- the array.

Fuad Ak
Fuad Ak
Courses Plus Student 691 Points

Thank you Dave for amazing js basic course, I loved it.!

Dino Paškvan
PLUS
Dino Paškvan
Courses Plus Student 44,108 Points
Dino Paškvan
Dino Paškvan
Courses Plus Student 44,108 Points

That's exactly it. return area + " " + unit; actually returns a single string.

Even if you were to return an array (containing multiple elements), or an object (containing multiple properties) that would still count as a single array/object.

Tom Lawrence
Tom Lawrence
8,685 Points
Tom Lawrence
Tom Lawrence
8,685 Points

thanks for your help thats all clear now and no problem Dave, the course was really good!

cesare
cesare
15,180 Points
cesare
cesare
15,180 Points

Create and return an array within two (or 3, 4, 5...) variables. :)

function returnArray(a, b){
    var c = a + b;
    var array = new Array(a, b, c);

    return array;
}

var myArray = returnArray(3, 5);

console.log(myArray[0] + " + " + myArray[1] + " = " + myArray[2]);