Question

我想访问一个嵌套的Json文件，并没有弄明白该怎么做：

  var createPromise = new Promise(function (resolve, reject) {
        ddpclient.call('create_emailConnection',[ddpclient.collections.email], function (err, result) {
          console.log([ddpclient.collections.email])
          resolve();
          if (err) {
            logger.error(0, '❌ error user_created')
          } else {
            logger.debug(5, 'users marked as created')
          }
        })
      })

此回归

email.json

{ HEDGz2aafs2UdSvT3S: 
     { _id: 'HEDGz2aafs2UdSvT3S',
       batch: '2017-user-created-by-websocket',
       creationIP: 'None',
       creationDate: 2018-06-14T13:23:58.786Z,
       state: [Object],
    },
    M101KSi360g7cER8D5: 
     { _id: 'M101KSi360g7cER8D5',
       batch: '2017-box-created-by-websocket',
       creationIP: 'None',
       creationDate: 2018-06-14T13:24:31.145Z,
       state: [Object],
      } }

所以我想在我的json文件上获取_id

Answer 1

因为，对象键HEDGz2aafs2UdSvT3S，M101KSi360g7cER8D5看起来是随机且不可预测的，因此您可以在数组对象上使用Object.keys()并循环遍历它们以获取_id的值

var arr = [ { HEDGz2aafs2UdSvT3S: 
     { _id: 'HEDGz2aafs2UdSvT3S',
       batch: '2017-user-created-by-websocket',
       creationIP: 'None',
       creationDate: '2018-06-14T13:23:58.786Z'
    },
    M101KSi360g7cER8D5: 
     { _id: 'M101KSi360g7cER8D5',
       batch: '2017-box-created-by-websocket',
       creationIP: 'None',
       creationDate: '2018-06-14T13:24:31.145Z'
      } } ];
      
arr.forEach((obj)=>{
  keys = Object.keys(obj);
  keys.forEach((key)=>{
   console.log(obj[key]._id);
  });
});

Answer 2

使用可以使用Array.reduce和Object.keys

您有array objects，每个object有多个objects，每个_id都映射到对象的key _ids。现在，您可以减少数组以连接所有key。由于对象的_id和_id相同，您可以使用对象的键来提取var arr = [{ HEDGz2aafs2UdSvT3S: { _id: 'HEDGz2aafs2UdSvT3S',batch: '2017-user-created-by-websocket',creationIP: 'None',creationDate: '2018-06-14T13:23:58.786Z'},M101KSi360g7cER8D5:{ _id: 'M101KSi360g7cER8D5',batch: '2017-box-created-by-websocket',creationIP: 'None',creationDate: '2018-06-14T13:24:31.145Z'} } ]; let ids = arr.reduce((a,c) => [...a, ...Object.keys(c)], []); console.log(ids);。

let obj = { HEDGz2aafs2UdSvT3S: { _id: 'HEDGz2aafs2UdSvT3S',batch: '2017-user-created-by-websocket',creationIP: 'None',creationDate: '2018-06-14T13:23:58.786Z'},M101KSi360g7cER8D5:{ _id: 'M101KSi360g7cER8D5',batch: '2017-box-created-by-websocket',creationIP: 'None',creationDate: '2018-06-14T13:24:31.145Z'} };
let ids = Object.keys(obj);
console.log(ids);

修改

{{1}}

Answer 3

试试这个：

a.map(x => Object.keys(x).map(y => x[y]._id))

这会返回一个属性数组_id。

小提琴：{{3}}

如何访问嵌套对象

3 个答案: