js数组去重

<script>
    /**数组去重*/
    function unique(arr){
        let start = (new Date()).getTime(); 
        let obj={};
        let data=[];
        for(let i=0;i<arr.length;i++){
            if(!obj[arr[i]]){
                data.push(arr[i]);
                obj[arr[i]] = true;
            }
        }
        let end = (new Date()).getTime(); 
        console.log("耗时：" + (end - start));
        return data;
    }
    
    
    
    /**数组去重 ES6*/
    function unique2(a){
        let start = (new Date()).getTime(); 
        let set = new Set(a);
        let ar = Array.from(set);
        let end = (new Date()).getTime(); 
        console.log("耗时：" + (end - start));
        return ar;
    }
</script>