遍历对象其中值是对象数组并从对象数组的每个对象返回一个值答案

【问题标题】：Iterating through object Where Value is Array of Objects and return one value from each Objects of Array of Objects遍历对象其中值是对象数组并从对象数组的每个对象返回一个值
【发布时间】：2019-12-13 00:53:11
【问题描述】：

如何从中获取所有office 值并将其存储为一个简单的数组？

var data = {
  'XYZ': [{
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'open',
      timestamp: '02-12-2019 00:15:29'
    },
    {
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'processed',
      timestamp: '02-12-2019 00:15:32'
    }
  ],
  'yyy': [{
      office: 'yyy.in',
      reportName: 'payroll',
      event: 'delivered',
      timestamp: '02-12-2019 00:15:29'
    },
    {
      office: 'yyy.in',
      reportName: 'payroll',
      event: 'open',
      timestamp: '02-12-2019 00:15:32'
    }
  ],
  'zzz': [{
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'delivered',
      timestamp: '02-12-2019 00:15:29'
    },
    {
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'open',
      timestamp: '02-12-2019 00:15:32'
    }
  ]
}

输出应该是这样的：

officesArray = ['xyz.in', 'yyy.in', 'xyz.in']

我的代码是

var Office = (Object.entries(grpDatas).flatMap(([k, v]) => (v.forEach(({office})=> office))))

它打印array of undefined。

【问题讨论】：

我已经编辑了问题。
这能回答你的问题吗？ From an array of objects, extract value of a property as array
为什么'xyz.in' 在结果集中出现两次？

标签： javascript arrays object

【解决方案1】：

使用map 而不是forEach 并且您访问的是email 而不是office：

var data = {
  'XYZ': [{
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'open',
      timestamp: '02-12-2019 00:15:29'
    },
    {
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'processed',
      timestamp: '02-12-2019 00:15:32'
    }
  ],
  'yyy': [{
      office: 'yyy.in',
      reportName: 'payroll',
      event: 'delivered',
      timestamp: '02-12-2019 00:15:29'
    },
    {
      office: 'yyy.in',
      reportName: 'payroll',
      event: 'open',
      timestamp: '02-12-2019 00:15:32'
    }
  ],
  'zzz': [{
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'delivered',
      timestamp: '02-12-2019 00:15:29'
    },
    {
      office: 'xyz.in',
      reportName: 'payroll',
      event: 'open',
      timestamp: '02-12-2019 00:15:32'
    }
  ]
}

var Email = Object.values(data).flatMap(item => [...new Set(item.map(({office})=> office))])
console.log(Email)

【讨论】：

我想以这种方式输出 ['xyz.in','yyy.in','xyz.in'] 我用过你的方式。
其实Object.entries这里也不需要，Object.values就够了。
但它返回 2 次，我只想要办公室的每个值。
@Amar 那么您需要在内部地图上使用Set 来删除重复项。我已经更新了答案。
是否可以过滤时间戳并根据该事件获取时间戳并将其存储到数组中？

【解决方案2】：

您可以从想要的属性中获取唯一值。

var data = { XYZ: [{ office: 'xyz.in', reportName: 'payroll', event: 'open', timestamp: '02-12-2019 00:15:29' }, { office: 'xyz.in', reportName: 'payroll', event: 'processed', timestamp: '02-12-2019 00:15:32' }], yyy: [{ office: 'yyy.in', reportName: 'payroll', event: 'delivered', timestamp: '02-12-2019 00:15:29' }, { office: 'yyy.in', reportName: 'payroll', event: 'open', timestamp: '02-12-2019 00:15:32' }], zzz: [{ office: 'xyz.in', reportName: 'payroll', event: 'delivered', timestamp: '02-12-2019 00:15:29' }, { office: 'xyz.in', reportName: 'payroll', event: 'open', timestamp: '02-12-2019 00:15:32' }] },
    office = Object.values(data).flatMap(v => [...new Set(v.map(({ office }) => office))]);

console.log(office);

【讨论】：

【解决方案3】：

const result = Object.keys(data) .map( key => data[key]) .flat() .map( element => element.office)

将所有内容转换为数组并将它们展平很有帮助！

https://codepen.io/t0dorakis/pen/MWYerKL

【讨论】：