arrayContainsSub matches arrays within arrays

arrayContainsSub.js

function arrayContainsSub(arr, sub) {
            var first = sub[0],
                i = 0,
                starts = [];

            while (arr.indexOf(first, i) >= 0) {
                starts.push(arr.indexOf(first, i));
                i = arr.indexOf(first, i) + 1;
            }

            return !!starts
                        .map(function(start) {
                            for (var i = start, j = 0; j < sub.length; i++, j++) {
                                if (arr[i] !== sub[j]) {
                                    return false;
                                }
                                if (j === sub.length - 1 && arr[i] === sub[j]) {
                                    return true;
                                }
                            };

                        }).filter(function(res) {
                            return res;
                        }).length;
        }