[JS] expanded string split function

/*
    split("hey ho what's up", ["-", "'", "."])
    -> returns ["hey ho what", "s up"]

    split("hey ho what's up", ["-", "'", "."], true)
    -> returns ["hey ho what", "'s up"]
*/
function split(inp, identifiers, withAppend) {
    if (typeof(withAppend) === 'undefined') withAppend = false;
    for (var i in identifiers) {
        var index = inp.indexOf(identifiers[i]);
        if (index > -1)
            return [inp.substr(0, index), inp.substr(withAppend ? index : index + 1, inp.length)];
    }
    return [inp];
}