Regex to match specific path with specific query param

General rule is that if you want to parse params, use URL parser, not a custom regex.

In this case you can use for instance:

# http://a.b/ is just added to make URL parsing work
url = new URL("http://a.b/page?foo=bar&target=1&test=1")
url.searchParams.get("target")
# => 1
url.pathname
# => '/page'

And then check those values in ifs:

url = new URL("http://a.b/page?foo=bar&target=1&test=1")

url = new URL("http://a.b/page?foo=bar&target=1&test=1")
if (url.searchParams.get("foo") && url.pathname == '/page' {
  # ...
}

See also:

• https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams
• https://developer.mozilla.org/en-US/docs/Web/API/URL

EDIT

If you have to use regex try this one:

\/page(?=\?).*[?&]target=[^&\s]*(&|$)

Demo

Explanation:

• \/page(?=\?) - matches path (starts with / then page then lookahead for ?)
• .*[?&]target=[^&\s]*($|&) matches param name target:
  • located anywhere (preceded by anything .*)
  • [?&] preceded with ? or &
  • followed by its value (=[^&\s]*)
  • ending with end of params ($) or another param (&)