Get the nth index of the
subjectis an array this must either be a function or a regular expression which will be tested against each element in
subjectis a string this must be a regular expression which will be tested against it to find all of the matches.
0represents the first occurrence whereas
-1represents the last.
targetcan be found within
subjectthe index will be returned otherwise
undefinedwill be returned.
This function requires the following function which is included automatically: