Character classes in regular expressions will match any of the characters enclosed in the square brackets ([abc] will match
a, b or c).
You can specify a range of characters using a hyphen (-). If the hyphen appears as the first or last character, it will be matched as
a literal hyphen.
An empty character class ([]) will not match any character because the set of matching characters is empty. So the regular expression
will not work as you intended.
/^foo[]/.test(str); // Noncompliant: always returns "false"
Use a non-empty character class or a different regular expression pattern that achieves the desired result.
/^foo/.test(str);
