regex allow white space, but do not begin or end with one, and not all white spaces

Question

I am trying to implement a regex rule that would allow users to enter white spaces, but it should not be all white spaces, nor begin or end with a white space. My research did not yield any workable solution. Currently, my rule looks like this, and I would like to add the white space requirement on top of that:

let string_rule = "^[a-zA-Z0-9_-]{3,16}$";

add some example and your wanted output – mjrezaee Jul 31 '20 at 15:45 — mjrezaee, Jul 31 '20 at 15:45

score 0 · Answer 1 · answered Jul 31 '20 at 15:47

0

let string_rule = "^\S[a-zA-Z0-9_-]{3,16}\S$";

answered Jul 31 '20 at 15:47

Shane

66
4

OP asked for not ending in a white space. I think you're missing a `^` before your second `\S`. – ThisIsAQuestion Jul 31 '20 at 15:50
there is a syntax error with this error, it resulted an error – Yugue Chen Aug 04 '20 at 17:09

score 0 · Answer 2 · answered Jul 31 '20 at 15:50

you can use following regex:

^(?:\S.*?\S|\S)$

Regex Demo

Details

^: start of string

\S.*?\S: first state which your input have more than 1 character, then its first and last character must exist and not to be spaces

\S: second state when your input consists of only one character

$: end of string

regex allow white space, but do not begin or end with one, and not all white spaces

2 Answers2