Re: code challenge: "Typeof and you: The mystery behind 'number', 'undefined' & 'string' as the value"

Hello all you budding, burdgeoning and blossoming scripters out there!

I have a question regarding the code challenge and the associated "typeof" operator.

Here's my solution

      function arrayCounter(array){
        if (typeof array === 'undefined' || typeof array === 'number' || typeof array === 'string' || array === 0){
            return 0;
          }
        return array.length;
      }

It works swimmingly but I had a bit of a problem figuring it out with just what we've learned for two reasons.

1. No proper explanation of <code>typeof</code>
2. actually, that's it...

The || operator has been explained elsewhere so I don't see a problem with expecting you to know that, but what I initially tried was this...

      function arrayCounter(array){
        if (typeof array === 'undefined' || typeof array === number || typeof array === string || array === 0){
            return 0;
          }
        return array.length;
      }

I had thought that you would use the keywords number and string. I understood from the video that you would use typeof array === 'undefined' with undefined wrapped in quotes but I did not think that number or string would also be wrapped in quotes.

Here was my thinking.

The word undefined gets returned as a value so it made sense that "ok, it compares array to the string 'undefined' so we wrap that in quotes and it works" but in wrapping the word string and number in quotes... that's where the logic of the whole thing escaped me.

I read the other thread and have learned that the better method is array.isArray(); but that was never taught and I have no issues with that not being taught as of yet. They were asking us to figure out how to do it with what we know and that as a teaching method is just fine. Plus, they did literally tell us in the code challenge specifications to use 'string' and 'number' in quotes although they didn't specifically say "make sure the words are wrapped in quotes as we've written here"

But anyway, my problem is this... what the heck does typeof actually do? How does it compare a number to a string value for example? You're literally telling the program to compare the type of data that exists in the argument that was passed but in each instance you're comparing it to a word that is a string.

So WHAT is the actual code that gets run via typeof? Now I'm figuring that it pulls in the data from the associated parameter that follows it (in this case the array parameter defined in the function) and then outputs a single word string based on what it finds... but what is the underlying CODE behind typeof? Is there anyway to find that out? Are we able to, somewhere, find the function that typeof runs to evaluate the data passed to it? How does it operate and what does it do to the data it receives to output those one word strings of 'undefined', 'string' and 'number'?

I guess that I don't REALLY have to know as long as I know how to use it, but that's how I work and it just bugs me until I know how the inner workings of a tool that I'm using actually does its job.

Thanks for any help or comments!

Cheers,

Huck -