Question: What is the best way to check if a single character is a whitespace?

I know how to check this through a regex.

But I am not sure if this is the best way if I only have a single character.

Isn't there a better way (concerning performance) for checking if it's a whitespace?

If I do something like this. I would miss white spaces like tabs I guess?

```
if (ch == ' ') {
    ...
}

```

Answer: 
The regex approach is a solid way to go. But here's what I do when I'm lazy and forget the proper regex syntax:

```
str.trim() === '' ? alert('just whitespace') : alert('not whitespace');

```
I have referenced the set of whitespace characters matched by PHP's [trim](http://php.net/trim) function without shame (minus the null byte, I have no idea how well browsers will handle that).

```
if (' \t\n\r\v'.indexOf(ch) > -1) {
    // ...
}

```

This looks like premature optimization to me though.