Regex to not match more than one trailing slash in string

Question

Looking for a regex to not match more than 1 occurrence of a trailing slash

api/v1
/api/v1
/api/2v1/21/
/api/blah/v1/
/api/ether/v1//
/api/23v1///

Expected match

/api/v1
/api/2v1/21/
/api/blah/v1/

What I tried:

^\/([^?&#\s]*)(^[\/{2,}\s])$

Answer 1

In the pattern that you tried, the second part of the pattern can not match, it asserts the start of the string ^ and then matches a single character in the character class (^[\/{2,}\s])$ directly followed by asserting the end of the string.

^\/([^?&#\s]*)(^[\/{2,}\s])$

              ^^^^^^^^^^^^^^

But you have already asserted the start of the string here ^\/

You can repeat a pattern starting with / followed by repeating 1+ times the character class that you already have:

^(?:\/[^\/?&#\s]+)+\/?$

Explanation

• ^ Start of string
• (?:\/[^\/?&#\s]+)+ Repeat 1+ times / and 1+ char other than the listed ones
• \/? Optional /
• $ End of string

See a regex demo