数组去重

  var a='1324564789798496465498'.split('');
        //方法1
        var b=new Set(a);
        console.log(Array.from(b))
        //方法2
        var c=a.reduce(function(total, num){
            //如果不存在 就push进去total
            !total.includes(num)&&total.push(num);
            return total;
        },[]);
        console.log(c)
        //方法3
        var d={};
        a.map(res=>{d[res]=res});
        console.log(Object.keys(d))