webpack - Regex to catch text not containing a string and ending with an extension

Question

I'm trying to have 2 regex, one catching string containing 'critrical' and ending with '(s)css' and second one for string which don't contain 'critical' (with the same extentions rule).

I already have the first one and it is /.*?critical.*.s?css$/

But I can't manage to make the second one. I thought it would be as easy as /.*?(?<!.critical).*.s?css$/. But, seems it's not that easy as it doesn't work...

Answer 1

Try this regex(for the string not containing the word critical and containing css in the end):

^(?!.*critical).*s?css$

Click for Demo

Explanation:

• ^ - asserts the start of the string
• (?!.*critical) - negative lookahead to validate that the word critical is not present in the string
• .* - matches 0+ occurrences(greedily) of any character except a new line
• s?css - matches an optional s followed by css
• $ - asserts the end of the string

And, for the string containing the word critical and containing css in the end, you can try:

^(?=.*critical).*s?css$

Click for Demo

The only difference with this regex is that it uses a Positive lookahead to make sure that the string critical exist somewhere in the string.