js数组去重

//去除重复数据
function filterRepeatStr(str) {
    var ar2 = str.split(",");
    ar2.sort();//先排序
    var res = [ar2[0]];
    for (var i = 1; i < ar2.length; i++) {
        if (ar2[i] !== res[res.length - 1]) {
            res.push(ar2[i]);
        }
    }
    return res.join(',');
}

返回值也是用逗号隔开的数组[1,2,3,4]