javascript - 使用 es6 创建嵌套对象

Question

我正在从本地 API 获取一些数据，不幸的是我对即将到来的数据没有太多控制，我希望我可以在 API 调用后使用函数转换数据。

这就是我目前拥有的

transformArray = () => {
    const { rawData } = this.state
    const obj = Object.fromEntries(
      rawData.map(category => [
        category,
        {
          aboveExpectation: rawData[0].value,
          atExpectation: rawData[1].value,
          belowExpectation: rawData[2].value,
        },
        console.log('category', category),
      ]),
    )
    console.log(obj)
  }

Output: [object Object]: {aboveExpectation: 6, atExpectation: 31, belowExpectation: 18}

从 API 返回的原始数据如下所示

    data [
  {
    "name": "Animal care",
    "Gap": "Above expectation",
    "value": 6
  },
  {
    "name": "Animal care",
    "Gap": "At expectation",
    "value": 31
  },
  {
    "name": "Animal care",
    "Gap": "Below expectation",
    "value": 18
  },
  {
    "name": "Calving and calf rearing",
    "Gap": "Above expectation",
    "value": 8
  },
  {
    "name": "Calving and calf rearing",
    "Gap": "At expectation",
    "value": 29
  },
  {
    "name": "Calving and calf rearing",
    "Gap": "Below expectation",
    "value": 18
  },
  {
    "name": "Reproduction",
    "Gap": "Above expectation",
    "value": 7
  },
  {
    "name": "Reproduction",
    "Gap": "At expectation",
    "value": 25
  },
  {
    "name": "Reproduction",
    "Gap": "Below expectation",
    "value": 23
  }
]

所以我不想要 9 个独立的对象，而是想要一些更可迭代的东西，像这样

"Animals": {
    "animalCare": {
      "atExpectation": 1,
      "aboveExpectation": 13,
      "belowExpectation": 15
    },
    "calvingAndCalfRearing": {
      "atExpectation": 1,
      "aboveExpectation": 13,
      "belowExpectation": 15
    },
    "Reproduction": {
      "atExpectation": 1,
      "aboveExpectation": 13,
      "belowExpectation": 15
    }
  },

现在我的transformArray函数已经取得了一些进展，但这并不完全是我想要的。我希望有人能指出我正确的方向

Answer 1

将对象数组简化为一个对象，并为每个name创建一个属性，并初始化/更新每个Gap的值:

const data = [{"name":"Animal care","Gap":"Above expectation","value":6},{"name":"Animal care","Gap":"At expectation","value":31},{"name":"Animal care","Gap":"Below expectation","value":18},{"name":"Calving and calf rearing","Gap":"Above expectation","value":8},{"name":"Calving and calf rearing","Gap":"At expectation","value":29},{"name":"Calving and calf rearing","Gap":"Below expectation","value":18},{"name":"Reproduction","Gap":"Above expectation","value":7},{"name":"Reproduction","Gap":"At expectation","value":25},{"name":"Reproduction","Gap":"Below expectation","value":23}]

const result = data.reduce((r, o) => {
  const name = r[o.name] || (r[o.name] = {}) // create an object for the name, or use the existing one
  name[o.Gap] = (name[o.Gap] || 0) + o.value; // add/update the Gap value

  return r
}, {})

console.log(result)