Parse query parameters with regexp

Question

I need to parse the url /domain.com?filter[abc]=value1&filter[abd]=value2 and get 2 groups: ' abc ' and ' abd '.

I try to parse with regexp [\\?&]filter\\[(.+\\..+)+\\]= but the result is ' abc]=value1&filter[abd '. How can I specify to search for the 1st occurrence?

Answer 1

You may use

/[?&]filter\[([^\].]+\.[^\]]+)]=/g

See the regex demo

Details

• [?&] - a ? or &
• filter\\[ - a filter[ substring
• ([^\\].]+\\.[^\\]]+) - Capturing group 1:
  • [^\\].]+ - 1 or more chars other than ] and .
  • \\. - a dot
  • [^\\]]+ - 1 or more chars other than ]
• ]= - a ]= substring

JS demo:

 var s = '/domain.com?filter[abc]=value1&filter[abd]=value2'; var rx = /[?&]filter\\[([^\\].]+\\.[^\\]]+)]=/g; var m, res=[]; while(m=rx.exec(s)) { res.push(m[1]); } console.log(res); 

Note that in case & is never present as part of the query param value, you may add it to the negated character classes, [^\\].]+ => [^\\]&.]+ , to make sure the regex does not overmatch across param values.

Since you need to extract text inside outer square brackets that may contain consecutive [...] substrings with at least 1 dot inside one of them, you may use a simpler regex with a bit more code:

 var strs = ['/domain.com?filter[abc]=value1&filter[abd]=value2', '/domain.com?filter[abc]=value1&filter[abd]=value2&filter[a][be]=value3', '/domain.com?filter[abc]=value1&filter[b][abd][d]=value2&filter[a][be]=value3']; var rx = /[?&]filter((?:\\[[^\\][]*])+)=/g; for (var s of strs) { var m, res=[]; console.log(s); while(m=rx.exec(s)) { if (m[1].indexOf('.') > -1) { res.push(m[1].substring(1,m[1].length-1)); } } console.log(res); console.log("--- NEXT STRING ----"); } 

Answer 2

(?<=[\?&]filter\[)([^\]]+\.[^\]]+)+(?!>\]=)

This will give you only the groups you mentioned ( abc and abd )

This part (?<=[\\?&]filter\\[) says recognise but don't capture [?&]filter before what you want and this part (?!>\\]=) says recognise but don't capture after ] after what you want.

[^\\]] this captures everything that isn't a square bracket