如何在DataWeave中使用groupBy实现指定格式输出？

输入示例 #

[
  { "item": 621, "orderid": "ON22", "qty": 45.0, "customer": "610", "date": "1988-08-13" },
  { "item": 63, "orderid": "ON2234", "qty": 7, "customer": "813", "date": "2001-08-13" }
]

期望输出示例 #

[
  {
    "customer":"813",
    "data":[
      { "item":63, "qty":7, "orderid":"ON2234", "date":"2001-08-13" }
    ]
  },
  {
    "customer":"610",
    "data":[
      { "item": 621, "qty": 45.0, "orderid": "ON22", "date": "1988-08-13" }
    ]
  }
]

实现思路（以JavaScript为例） #

通过Array.prototype.reduce()先按customer完成分组，再将分组结果转换为目标结构：

const orders = [
  { "item": 621, "orderid": "ON22", "qty": 45.0, "customer": "610", "date": "1988-08-13" },
  { "item": 63, "orderid": "ON2234", "qty": 7, "customer": "813", "date": "2001-08-13" }
];

// 1. 按customer分组，构建客户-订单列表的映射
const customerMap = orders.reduce((acc, order) => {
  const { customer, ...orderDetail } = order;
  if (!acc[customer]) {
    acc[customer] = [];
  }
  acc[customer].push(orderDetail);
  return acc;
}, {});

// 2. 将映射转换为目标数组格式
const result = Object.entries(customerMap).map(([customer, data]) => ({
  customer,
  data
}));

console.log(result);

代码说明 #

• 分组阶段：遍历订单数组，以客户ID为键，将去除customer字段后的订单详情存入对应数组，形成{ 客户ID: [订单详情数组] }的映射结构。
• 格式转换阶段：提取映射的键值对，直接映射为期望的{customer, data}对象数组。

如果同一客户存在多个不同orderid的订单，该代码也能自动将所有订单归入对应客户的data数组，满足按客户分组的需求。

内容的提问来源于stack exchange，提问作者james11