lastIndexOf.js #1

define(function () {

    /**
     * Array lastIndexOf
     */
    function lastIndexOf(arr, item, fromIndex) {
        if (arr == null) {
            return -1;
        }

        var len = arr.length;
        fromIndex = (fromIndex == null || fromIndex >= len)? len - 1 : fromIndex;
        fromIndex = (fromIndex < 0)? len + fromIndex : fromIndex;

        while (fromIndex >= 0) {
            // we iterate over sparse items since there is no way to make it
            // work properly on IE 7-8. see #64
            if (arr[fromIndex] === item) {
                return fromIndex;
            }
            fromIndex--;
        }

        return -1;
    }

    return lastIndexOf;
});