Check if a single character is a whitespace?

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 onl

Answer 1

While it's not entirely correct, I use this pragmatic and fast solution:

if (ch.charCodeAt(0) <= 32) {...

Answer 2

@jake 's answer above -- using the trim() method -- is the best option. If you have a single character ch as a hex number:

String.fromCharCode(ch).trim() === ""

will return true for all whitespace characters.

Unfortunately, comparison like <=32 will not catch all whitespace characters. For example; 0xA0 (non-breaking space) is treated as whitespace in Javascript and yet it is > 32. Searching using indexOf() with a string like "\t\n\r\v" will be incorrect for the same reason.

Here's a short JS snippet that illustrates this: https://repl.it/@saleemsiddiqui/JavascriptStringTrim

Answer 3

this covers spaces, tabs and newlines:

if ((ch == ' ') || (ch == '\t') || (ch == '\n'))

this should be best for performance. put the whitespace character you expect to be most likely, first.

if performance is really important, probably best to consider the bigger picture than individual operations like this...