javascript regex how to match only parts in a list with mandatory prefix

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I want to match ": red", ": 10", ": [special]" only if category present before (I want to use replace function to get rid of them afterwards)

category fruit(color: red, size: 10, others: [special])

I have this regex for above

(((:\s*[\w\[\]]+)(?=[,\)]))+)

except for category, I can't seem to be able to use lookbehind for that.

javascript regex
2 Answers

If we take the the following input verbatim:

Figure I - Input String

category fruit(color: red, size: 10, others: [special])

Using a positive lookbehind to match literal : red, : 10, and : [special]:

Figure II

/(?<=category[\S\s]+?)(:\s?red|:\s?10|:\s?\[special\])/g

Figure III

Segment Description
(?<=category[\S\s]+?) Match, but do not consume, literal "categorey", anything in between if it proceeds...
(:\s?red|:\s?10|:\s?\[special\]) ...literal colon, zero to one space, literal "read" OR literal colon, zero to one space, literal "10" OR literal colon, zero to one space, literal "[special]"

See Regex101

Jeffery Flynt commented that it isn't syntactically correct, I'd have to agree

user_28132240

If you want to match word characters before the colon and either word characters after the colon or from[...], and the values have to be between parenthesis, then you might also use:

(?<=\bcategory\s[^()]*\([^()]*\w):\s*(?:\w+|\[[^\[\]]*\])(?=[^()]*\))

Explanation

  • (?<= Positive lookbehind assertion, check what is to the left is:
    • \bcategory\s+[^()]* Match the word category, followed by whitespace chars and optionally any char except parenthesis
    • \([^()]*\w Match ( and again any char except parenthesis followed by a word char
  • ) Close the lookbehind
  • :\s* Match : and optional whitespace chars
  • (?:\w+|\[[^\[\]]*\]) Match either 1+ word chars, or match from [...]
  • (?=[^()]*\)) Positive lookahead, assert ) to the right

Regex demo

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