If Anything Equals NaN

Question

Is it possible to write something like:

 if( * === NaN){
          this = 0;  
        };

What I'm trying to do is catch any math or variables that calculate as NaN and make them equal to 0. I could write the same if statement for each time math is done but it would be messy and I was hoping there was a simple solution like this.

Well, you would need to use [`isNaN`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN) and you can't assign to `this`. `this = anything` is invalid. — Mike Cluck, Aug 19 '16 at 17:07
You need to look at all the variables, there is no "everything" — epascarello, Aug 19 '16 at 17:07
As a shorthand you may be able to use `(varname || 0)`, as this will (among other things) keep numeric values as they are but replace `NaN` (falsy value) with `0`. — Niet the Dark Absol, Aug 19 '16 at 17:08
Hey Yury, that was a loose example to get the point across of the intention as I said. You could substitute: isNan(*anythingHere) == true — D. Cantatore, Aug 20 '16 at 19:24

score 0 · Answer 1 · answered Aug 19 '16 at 17:10

I don't think so, since as far as I know nothing is equal to NaN. However, you can take advantage of that and do:

if( * !== *){
      //code when * is NaN  
    };

And only a NaN will meet the condition. I read this is safer than just to use isNaN() .

score 0 · Answer 2 · answered Aug 19 '16 at 17:20

0

You can do something like this

function convertIfNaN (x) {
    if (isNaN(x))
        return 0;
    else
        return x;
}

answered Aug 19 '16 at 17:20

yitzih

3,018
3
27
44

dalyhabit · Answer 3 · 2016-08-20T23:43:11.203

0

You can use the isNaN function like so:

if (isNaN(x)) {
    // do something
}

The built in isNaN function will only check if the value can be coerced to a number. You can also write your own function to simply check for the value "NaN" like so:

function isNaN(x){
  return x !== x;
}

edited Aug 20 '16 at 23:43

answered Aug 19 '16 at 17:26

dalyhabit

29
4

I think this is the closest to what I was looking to achieve. It appears the simple clever code option doesn't really fit the situation and I just did a copy paste of a small if statement to check each time the variable would be used before it was used. Thanks! – D. Cantatore Aug 20 '16 at 19:28

If Anything Equals NaN

3 Answers3