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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Random Number Challenge, Part II Solution

Posted by Agan Murali
Agan Murali
Courses Plus Student 893 Points

"isNaN" is not a best suit for this program.

When you parse an argument like this "isNaN("1000", 2000)" this will return "false", because it's not checking what type it is. But I used this as a condition in order to solve that problem,

typeof(lower) === 'number' && typeof(upper) === 'number'

is it ok or does it have any best way to do.

2 Answers

Bernadette Guevarra
Bernadette Guevarra
16,295 Points
Bernadette Guevarra
Bernadette Guevarra
16,295 Points

isNaN stands for "is Not a Number", so it's like this, is ("1000") not a number? False, since js interprets this number in the string as a number (as long as it's only numbers inside the string, no spaces or other characters). Is ("a1000") not a number? True, since js interprets this alphanumeric string as a string. I played on the console in the developer tool a bit to see various results with isNaN, and it's quite helpful.

Andy Birchwood
Andy Birchwood
3,703 Points
Andy Birchwood
Andy Birchwood
3,703 Points

As I was trying the challenge, this confused me, because I used a number in the string to test isNan would return true and it didn't. It also made a calculation using the string as a parameter, but I'm not sure how...

babasariffodeen
babasariffodeen
6,475 Points

Hi Andy,

Just read your comment and wanted to clarify according to how I understand isNAN to work.

You mentioned you "used a number in the string to test isNan would return true and it didn't".

isNAN would return true if you parse something that is not a number.

So isNAN("a55") would be true because a55 is truly not a number. However, isNAN(60) would be false because it would be false to say that 60 is not a number.

Hope that helps.