Gets the index of a specified target value in a string, array or an object. Unlike
Array.prototype.indexOf(), this function works for finding
NaN and differentiates between
targetshould be searched for.
subjectis an array or a string this will be a integer representing the first position at which
targetis found within
subjector this will be
-1which represents that
targetwas not found. If
subjectis an object this will be key at which
targetwas first found (based on
targetwas not found.
This function requires the following function which is included automatically: