js 数组去除重复项

转自司超云，连接地址忘记了。。

//去除已选检查项数组中重复项
 var compare = compare || {};
    compare.array = compare.array || {};
 compare.array.unique = function (source, compareFn) {
     var len = source.length,
         result = source.slice(0),
         i, datum;
        
     if ('function' != typeof compareFn) {
         compareFn = function (item1, item2) {
             return item1 === item2;
         };
     }
     // 从后往前双重循环比较
     // 如果两个元素相同，删除后一个
     while (--len > 0) {
         datum = result[len];
         i = len;
         while (i--) {
             if (compareFn(datum, result[i])) {
                 result.splice(len, 1);
                 break;
             }
         }
     }
     return result;
 };