js：写一个函数，实现数组[1,2,2,3,5,4,3,3,3,3,5,4,6,7,6,9,9,9,9]的去重

以下是实现数组去重的JS函数代码：

function unique(arr){
    var result = [];
    for(var i=0; i<arr.length; i++){
        if(result.indexOf(arr[i]) == -1){
            result.push(arr[i]);
        }
    }
    return result;
}

var arr = [1,2,2,3,5,4,3,3,3,3,5,4,6,7,6,9,9,9,9];
var newArr = unique(arr);
console.log(newArr);