对比两个对象数组按Id匹配计算Qty差值，生成新数组及删除订单数组（禁用ES6）

数据老陈

2026-10-2

实现方案

你可以直接封装一个独立的处理函数，一次性返回需要的两个结果数组，全程使用ES5语法，没有用到任何ES6特性，代码如下：

function processOrders(oldOrder, newOrder) {
  var oldIdMap = {};
  var newArray = [];
  var droppedOrders = [];
  var i, len, currentId, currentQty;

  // 把老订单的Id、对应数量存入映射表，添加匹配标记
  for (i = 0, len = oldOrder.length; i < len; i++) {
    currentId = oldOrder[i].Id;
    oldIdMap[currentId] = {
      qty: oldOrder[i].Qty,
      matched: false
    };
  }

  // 遍历新订单生成newArray
  for (i = 0, len = newOrder.length; i < len; i++) {
    currentId = newOrder[i].Id;
    currentQty = newOrder[i].Qty;
    if (oldIdMap.hasOwnProperty(currentId)) {
      // 两个订单都存在的Id，Qty取差值
      newArray.push({
        Id: currentId,
        Qty: currentQty - oldIdMap[currentId].qty
      });
      oldIdMap[currentId].matched = true;
    } else {
      // 仅新订单存在的Id，直接加入结果
      newArray.push({
        Id: currentId,
        Qty: currentQty
      });
    }
  }

  // 收集仅在老订单存在的droppedOrders
  for (currentId in oldIdMap) {
    if (oldIdMap.hasOwnProperty(currentId) && !oldIdMap[currentId].matched) {
      droppedOrders.push({
        Id: currentId,
        Qty: oldIdMap[currentId].qty
      });
    }
  }

  // 同时返回两个结果
  return {
    newArray: newArray,
    droppedOrders: droppedOrders
  };
}

调用方式

直接传入两个订单数组即可拿到对应结果，示例如下：

var oldOrder = [{"Id": "10","Qty": 1}, {"Id": "3","Qty": 2}, {"Id": "9","Qty": 2}]; 
var newOrder = [{"Id": "5","Qty": 2},{"Id": "10","Qty": 3}, {"Id": "9","Qty": 1}];

var result = processOrders(oldOrder, newOrder);
var newArray = result.newArray;
var droppedOrders = result.droppedOrders;