Javascript Regex negative lookbehind Alternative

Question

Looks like it is not first question about look-behind, but I didn't find an answer.

Javascript has no (positive|negative)look-behind requests.

I need a regular expression that match *.scss file name, but didn't match the names like *.h.scss. With look-behind request is looks like:

/(?<!(\.h))\.scss$/

How can I do this in javascript? I need this regular expression for webpack rules "test" parameter, so the javascript regex required only.

can someone please answer following: https://stackoverflow.com/q/59403483/11264185 — Shivam Poojara, Dec 19 '19 at 06:51

score 5 · Accepted Answer · answered Feb 10 '18 at 23:09

You may use

/^(?!.*\.h\.scss$).*\.scss$/

Details

^ - start of string anchor
(?!.*\.h\.scss$) - a negative lookahead failing the match if the string ends with .h.scss
.* - any 0+ chars as many as possible
\.scss - a .scss substring at the...
$ - end of the string.

score 4 · Answer 2 · answered Feb 10 '18 at 23:25

4

You can list all possible subpatterns that doesn't match .h and build an alternation:

/(?:[^.].|\.[^h]|^.?)\.scss$/

answered Feb 10 '18 at 23:25

Thank you for reply, this working solution too, but answer of [Wiktor Stribiżew](https://stackoverflow.com/users/3832970/wiktor-stribi%c5%bcew) is more simplier to understand. – Jonik Feb 11 '18 at 12:41

2 Answers2