findNthIndex()Get the nth index of the target in subject.
target in.subject is an array this must either be a function or a regular expression which will be tested against each element in subject. If subject is a string this must be a regular expression which will be tested against it to find all of the matches.0 represents the first occurrence whereas -1 represents the last.target can be found within subject the index will be returned otherwise undefined will be returned.This function directly requires the following function which is included automatically:
findNth()target in subject.
This function is directly required by the following function:
findNth()target in subject.