如何找到嵌套在数组中的对象键的差异答案

【问题标题】：how to find a diff of object keys nested in array如何找到嵌套在数组中的对象键的差异
【发布时间】：2021-11-05 08:48:53
【问题描述】：

我有 3 个对象，它们有一个“成本”键，它是对象数组。结果，我想要一个“main”，它保持不变，除了它的“value”将是这个值减去其他对象“value”的差异

const main = {
  cost: [
    { id: 'main', value: 20, timestapm: 'asd', current: '10'},
    { id: 'main', value: 10, timestapm: 'asd', current: '10'},
    { id: 'main', value: 18, timestapm: 'asd', current: '10'},
  ],
  description: 'maindevice',
  total: 5
}

const other = {
  cost: [
    { id: 'device1', value: 10, timestapm: 'qwe', current: '10'},
    { id: 'device1', value: 5, timestapm: 'qwe', current: '10'},
    { id: 'device1', value: 9, timestapm: 'qwe', current: '10'},
  ],
  description: 'maindevice',
  total: 3
}

const other2 = {
  cost: [
    { id: 'device2', value: 5, timestapm: 'zxc', current: '10'},
    { id: 'device2', value: 2, timestapm: 'zxc', current: '10'},
    { id: 'device2', value: 2, timestapm: 'zxc', current: '10'},
  ],
  description: 'maindevice',
  total: 6
}

const devices = [main, other, other2];

result i want to have => 

main = {
  cost: [
    { id: 'main', value: 5, timestapm: 'asd', current: '10'},
    { id: 'main', value: 3, timestapm: 'asd', current: '10'},
    { id: 'main', value: 7, timestapm: 'asd', current: '10'},
  ],
  description: 'maindevice',
  total: 5
}

【问题讨论】：

什么不起作用？
我不知道该怎么做。我可以找到只有 3 个数组的差异，但是当这个数组嵌套在一个对象中时，我不知道该怎么做
你想改变main吗？
@NinaScholz 是的，我可以改变它

标签： javascript arrays object

【解决方案1】：

const calcNewValue = (main, other, other2) => {
    main.cost = main.cost.map((obj, index) => { return {...obj, value: value=other.cost[index].value - other2.cost[index].value}})
    return main
}

这对你有用

【讨论】：

【解决方案2】：

您可以减少 devices 并改变数组的第一个对象。

const
    main = { cost: [{ id: 'main', value: 20, timestamp: 'asd', current: '10'}, { id: 'main', value: 10, timestapm: 'asd', current: '10'}, { id: 'main', value: 18, timestapm: 'asd', current: '10'}], description: 'maindevice', total: 5 },
    other = { cost: [{ id: 'device1', value: 10, timestamp: 'qwe', current: '10'}, { id: 'device1', value: 5, timestapm: 'qwe', current: '10'}, { id: 'device1', value: 9, timestapm: 'qwe', current: '10'}], description: 'maindevice', total: 3 },
    other2 = { cost: [{ id: 'device2', value: 5, timestamp: 'zxc', current: '10'}, { id: 'device2', value: 2, timestapm: 'zxc', current: '10'}, { id: 'device2', value: 2, timestapm: 'zxc', current: '10'}], description: 'maindevice', total: 6 },
    devices = [main, other, other2];

devices.reduce((r, o) => {
    o.cost.forEach(({ value }, i) => r.cost[i].value -= value);
    return r;
});

console.log(main);

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【讨论】：