Xregexp javascript optional named group seperated by white spaces

Question

I'm looking into an Xregexp expression that support named parameter preceded by letters . Here is my expression :

(?:d:|duration:)(?<time>.*\S+).*(?:t:|title:)(?<title>(?:.*\S+))(?:.*(?:(?:p:|prize:)(?<prize>.*\S+)))

It is working well, but the problem is I wanna put the p:<prize> group as optional, Which expression should I use ?

I'm also trying to end the capture when there is a white space

Example:

What I want :

duration:1h 5m 1s title:Title test [p:prize]<-optionnal group

I want to have the prize group as optional

Match with the current expression :

duration:1h 5m 1s title:Title test p:Something random

Group results:

• time : 1h 5m 1s

• title : Title test

• prize : Something random

Answer 1

You need to restrict your patterns a bit to get rid of .* that would eat up all up to the last occurrences of subsequent subpatterns. Then, use lazy dot pattern (.*?) whenever you need to match a value up to the next key, and add a $ (end of string) anchor at the end to make sure you will get all the text with the lazy dots.

d(?:uration)?:(?<time>.*?)\s*t(?:itle)?:(?<title>.*?)\s*(?:p(?:rize)?:(?<prize>.*))?$

See the regex pattern.

Details

• d(?:uration)?: - a d: or duration:
• (?<time>.*?) - Group "time": any zero or more chars, as few as possible, up to the leftmost occurrence of the subsequent subpatterns
• \s* - 0+ whitespaces
• t(?:itle)?: - either title: or t:
• (?<title>.*?)- Group "title": any zero or more chars, as few as possible
• \s* - 0+ whitespaces
• (?: - start of an optional non-capturing group matching 1 or 0 occurrences of:
  • p(?:rize)?: - p: or prize:
  • (?<prize>.*) - Group "prize": any zero or more chars, as few as possible
• )? - end of the optional group
• $ - end of string.