JS how to check empty String and Space

Question

Help me pls

if(value == ""){
// do anything
}

but I need to check space " " (2,3,... space is include) is the same way of empty String

ps. sorry in my English

@Andrew - It's not a duplicate at all. That other question has nothing to do with detecting strings containing only spaces. — RJM, Apr 08 '16 at 03:40
@RJM There are numerous answers on that question that handle: null/undefined and only-whitespace input. See, for example, [this answer](http://stackoverflow.com/a/3261380/279608) — Andrew, Apr 08 '16 at 03:45
sorry man I need to check String with whitespace only is same as empty String — JinkleBell Surcharoen, Apr 08 '16 at 03:45

4castle · Accepted Answer · 2021-07-21T14:43:01.900

12

A regex can easily solve this problem.

if (/^ *$/.test(value)) {
    //string contains 0+ spaces only
}

If you need to include null also, then add !value ||.

If you need to include newlines, tabs, and the like, then use /^\s*$/ for the regex.

edited Jul 21 '21 at 14:43

answered Apr 08 '16 at 03:44

4castle

Why regex and not `if (!value || !value.trim()) { //null or empty }`. Matches empty strings, tabs, newline characters – pcvnes Sep 17 '21 at 10:52
@pcvnes That works fine too – 4castle Sep 17 '21 at 13:10

score -1 · Answer 2 · answered Apr 08 '16 at 03:28

-1

I'm not sure I'm understanding correctly. Do you mean like:

if (value == "" || value == " "){
// do anything
}

answered Apr 08 '16 at 03:28

RJM

sorry I need 2,3,4,... space too – JinkleBell Surcharoen Apr 08 '16 at 03:29
willie's answer will do the job. Just beware of the caveat I mention in the comments. – RJM Apr 08 '16 at 03:32

2 Answers2