Use-recursion-to-create-a-range-of-numbers

[NathanVu]

function rangeOfNumber(startNum, endNum){
if (endNum< startNum){
return ;
}else {
var countArray = rangeOfNumber(startNum, endNum -1);
countArray.push(endNum);
return countArray;
}
}
console.log(rangeOfNumber(1,7))

Line 6 was a bit confusing. Push method enables you to push a number to the end of the array. You’re pushing endNum into CountArray when it’s not an array. I understand most of it. Just that was part to me was ambiguous.

[JeremyLT]

@NathanVu

var countArray = rangeOfNumber(startNum, endNum -1);

This function call creates countArray

[NathanVu]

@NathanVu

if (endNum< startNum){
return ;
}else {
var countArray = rangeOfNumber(startNum, endNum -1);
countArray.push(endNum);
return countArray;
}
}
console.log(rangeOfNumber(1,7))

Right but we’re just reassigning the recursive to the countArray variable. What happens to countArray.push(endNum); ? 7-1= 6, all the way until we get 1. I don’t understand how it get’s pushed into an array.

[JeremyLT]

@NathanVu

just reassigning the recursive

What do you mean?

Each function call and return value is separate. A call to ranguOfNumber always returns an array. That array always has the numbers from the value of the first argument to the value of the second argument.

[twotani]

Here’s how the recursive calls are working. Each function call will result in an array coming back.

[NathanVu]

Holy crap. Thank you so much for the explanation. I thought it returns an empty array once. You guys are the best!

[NathanVu]

Reread and tried it a couple of times now. Appreciate your help Jeremy!