将对象父键附加到孩子

Question

我有以下对象：

{
  "groupA": [
    {data: 'foo'},
    {data: 'bar'}
  ],
  "groupB": [
    {data: 'hi'},
    {data: 'mom'}
  ]
}

我想将父对象键添加到其所有数组项目中：

{
  "groupA": [
    {data: 'foo', set: 'groupA'},
    {data: 'bar', set: 'groupA'}
  ],
  "groupB": [
    {data: 'hi', set: 'groupB'},
    {data: 'mom', set: 'groupB'}
  ]
}

如何实现？

Answer 1

这是一个不变的版本，它可以使用object.fromentries Object.entries和map为您提供新对象。

const data = {
  "groupA": [{
      data: 'foo'
    },
    {
      data: 'bar'
    }
  ],
  "groupB": [{
      data: 'hi'
    },
    {
      data: 'mom'
    }
  ]
}

const withGroup = Object.fromEntries(
     Object.entries(data).map(([set, items]) => [set, items.map(i => ({ ...i,set}))])
)

console.log(withGroup)

Answer 2

您可以循环并设置每个项目

const obj = {
  "groupA": [
    {data: 'foo'},
    {data: 'bar'}
  ],
  "groupB": [
    {data: 'hi'},
    {data: 'mom'}
  ]
};
Object.entries(obj).forEach(([key,val]) => val.forEach(item => item.set=key))
console.log(obj)

Answer 3

您可以通过在对象上循环并映射数组来做到这一点，例如：

const data = {
  "groupA": [
    {data: 'foo'},
    {data: 'bar'}
  ],
  "groupB": [
    {data: 'hi'},
    {data: 'mom'}
  ]
};

Object.keys(data).forEach(key => {
    data[key] = data[key].map(rec => ({...rec, set: key}));
})

console.log(data);

Answer 4

您也可以在中使用

let data = {
  "groupA": [
    {data: 'foo'},
    {data: 'bar'}
  ],
  "groupB": [
    {data: 'hi'},
    {data: 'mom'}
  ]
}

for (const key in data) {
  data[key] = data[key].map(item => ({...item, set: key}))
}

console.log(data);

Answer 5

您可以尝试object.keys（arr）获取所有密钥名称：

let before = {
  "groupA": [
    {data: 'foo'},
    {data: 'bar'}
  ],
  "groupB": [
    {data: 'hi'},
    {data: 'mom'}
  ]
}

let after = {}
Object.keys(before).map((key) => {
    let data = before[key].map((x) => { 
        x.set = key
        return x
    })
    after[key] = data 
})
console.log(before)
console.log(after)

============

[update] 在之后创建 之前：

    let before = {
    "groupA": [
        {data: 'foo'},
        {data: 'bar'}
    ],
    "groupB": [
        {data: 'hi'},
        {data: 'mom'}
    ]
}

let after = {}
Object.entries(before).forEach(([key, data]) => {
    after[key] = data.map((before_value) => { 
        return { 
            ...before_value, 
            set: key
          }
    })
})
console.log(before)
console.log(after)