There are several reasons to use a group in a regular expression:
- to change the precedence (e.g.
/do(g|or)/ will match 'dog' and 'door')
- to remember parenthesised part of the match in the case of capturing group
- to improve readability
In any case, having an empty group is most probably a mistake. Either it is a leftover after refactoring and should be removed, or the actual
parentheses were intended and were not escaped.
Noncompliant Code Example
"/foo()/" // Noncompliant, will match only 'foo'
"/foo\(\)/" // Matches 'foo()'