Question

我具有如下结构-

var a = {
  foo: {
    dates: {'2018-11-29': 2020.55},
    strategies: [
      {
        expiryDate: '2018-11-29',
        projects: [
          {
            expiryDate: '2018-11-29',
            name: 'foo',
            value: 500
          }
        ]
      }
    ]
  },
  bar: {
    dates: {'2018-11-29': 2020.55},
    strategies: [
      {
        expiryDate: '2018-11-29',
        projects: [
          {
            expiryDate: '2018-11-22',
            name: 'bar',
            value: 650
          },
          {
            expiryDate: '2018-11-22',
            name: 'mario',
            value: 700
          }
        ]
      }
    ]
  }
}

我正在尝试找到一种方法，可以使用lodash轻松更新内部projects集合。但是我遇到了错误

我正在尝试做这样的事情

const finalTransformedData = _.mapValues(
  a,
  (value, key) => {
    value.strategies.map(strats =>
      strats.projects.map(trade =>
        Object.assign(
          {},
          { trade: 1 },
        ),
      ),
    );
  },
);

但是我得到以下输出-我在哪里错了？

{ foo: undefined, bar: undefined }

上面的示例代码有点过分简化，但是我要寻找的是以某种方式轻松地操作项目数组中的对象-本质上是这样的-通过遍历对象并分配新的对象来替换数组中的对象对象（从object.assign获取）

foo: {
    dates: {'2018-11-29': 2020.55},
    strategies: [
      {
        expiryDate: '2018-11-29',
        projects: [
          {
            trade: 1
          }
        ]
      }
    ]
  },
  bar: {
    dates: {'2018-11-29': 2020.55},
    strategies: [
      {
        expiryDate: '2018-11-29',
        projects: [
          {
            trade: 1
          },
          {
            trade: 1
          }
        ]
      }
    ]
  }

Answer 1

如果没有lodash，您也可以尝试循环for..of

var a = {  foo: {    dates: {'2018-11-29': 2020.55},    strategies: [      {        expiryDate: '2018-11-29',        projects: [          {            expiryDate: '2018-11-29',            name: 'foo',            value: 500          }        ]      }    ]  },  bar: {    dates: {'2018-11-29': 2020.55},    strategies: [      {        expiryDate: '2018-11-29',        projects: [          {            expiryDate: '2018-11-22',            name: 'bar',            value: 650          },          {            expiryDate: '2018-11-22',            name: 'mario',            value: 700          }        ]      }    ]  }}

for(let { strategies } of Object.values(a)) {
  for(let s of strategies) {
    s.projects = s.projects.map(d => ({ trade: 1 }))
  }
}

console.log(a)

Answer 2

请勿为此使用lodash。而是使用immer-https://github.com/mweststrate/immer

您可以这样做：

const finalTransformedData = produce(
  a,
  (draft) =>
    draft.strategies.forEach(strats =>
      strats.projects.forEach(project => {
        project.trade = 1
      })
    ),
);

更新集合中深层嵌套的对象

2 个答案: