数组去重

　　　　　　　function getOne(a,b){
                var arr = a.concat(b);
                return arr.filter(function(item,index){
                    return arr.indexOf(item) === index;
                })
            }
            var a = ["aaa","bbb","ccc","ddd","eee"];
            var b = ["ccc","ddd","eee","fff","gg"];
            console.log(getOne(a,b)) 

            function getOne(a,b){
                var arr1 = a.concat(b)
                var arr2 = [];
                var obj = {};
                for(var i of arr1){
                    if(!obj[i]){
                        arr2.push(i)
                        obj[i] = 111
                    }
                }
                return arr2
            }
            var a = ["aaa","bbb","ccc","ddd","eee"];
            var b = ["ccc","ddd","eee","fff","gg"];
            console.log(getOne(a,b))