JS如何实现JSON数组内的去重算法

paylist:[{paymode:'1',payname:"现金"，paymoney:"20"},
{paymode:'2',payname:"支付宝"，paymoney:"50"},{paymode:'1',payname:"现金"，paymoney:"40"}]

function UniquePay(paylist){
  var payArr = [paylist[0]];
  for(var i = 1; i < paylist.length; i++){
    var payItem = paylist[i];
    var repeat = false;
    for (var j = 0; j < payArr.length; j++) {
     if (payItem.paymode == payArr[j].paymode) {
        payArr[j].paymoney = parseFloat(payArr[j].paymoney)+parseFloat(payItem.paymoney);
         repeat = true;
         break;
     }
   }
       if (!repeat) {
         payArr.push(payItem);
       }
  }
  return payArr;
}

/*
 * JSON数组去重
 * @param: [array] json Array
 * @param: [string] 唯一的key名，根据此键名进行去重
 */
function uniqueArray(array, key){
  var result = [array[0]];
  for(var i = 1; i < array.length; i++){
    var item = array[i];
    var repeat = false;
    for (var j = 0; j < result.length; j++) {
      if (item[key] == result[j][key]) {
        repeat = true;
        break;
      }
    }
    if (!repeat) {
      result.push(item);
    }
  }
  return result;
}