数组去重 filter

let arr = ['1',"2","1"];

    //剔除指定数据
    remove(arr, item) {
        return arr.filter(val => val != item);
    }
    //数组去重
    arrs(arr){
        return  arr.filter(function (element, index) {
            return arr.indexOf(element) == index;
        })
    },