JavaScript过滤除连续的数字

if (!Array.prototype.forEach) {
    Array.prototype.forEach = function (callback, thisArg) {
        var T, k;
        if (this == null) {
            throw new TypeError(" this is null or not defined");
        }
        var O = Object(this);
        var len = O.length >>> 0; // Hack to convert O.length to a UInt32
        if ({}.toString.call(callback) != "[object Function]") {
            throw new TypeError(callback + " is not a function");
        }
        if (thisArg) {
            T = thisArg;
        }
        k = 0;
        while (k < len) {
            var kValue;
            if (k in O) {
                kValue = O[k];
                callback.call(T, kValue, k, O);
            }
            k++;
        }
    };
}

//筛选连续的数字
        function arrange(source) {
            var t;
            var ta;
            var r = [];

            source.forEach(function (v) {
                //console.log(t, v);   // 跟踪调试用
                if (t === v) {
                    ta.push(t);
                    t++;
                    return;
                }

                ta = [v];
                t = v + 1;
                r.push(ta);
            });

            return r;
        }

//测试
var arr=[1,5,6,8,11,12];
arrange(arr);

返回:[[1],[5],[6],[8],[11,12]]