JS数组查重、数组对象求差集

var uuidArr = ["bbb","vvv","aaa","fff","fff"],flag = true;
    var arr1 = [
        {"rolename":"aaa"},
        {"rolename":"bbb"},
        {"rolename":"ccc"},
        {"rolename":"ddd"}
    ];
    var arr2 = [
        {"rolename":"eee"},
        {"rolename":"ccc"},
        {"rolename":"aaa"},
        {"rolename":"fff"}
    ];

    // 数组查重
    for(let i = 0; i < uuidArr.length; i++){
        for(let j = i+1; j < uuidArr.length; j++){
            if(uuidArr[i] == uuidArr[j]){
                flag = false;
                break;
            }
        }
    }
    if(!flag){
        alert("有相同项！");
    }else{
        alert("都不相同")
    }
    //数组求差
    function getSubtract(unionArr,subsetArr)
    {
        var new_tmp = new Array();
        for(var i=0;i