如何使用lodash或javascript过滤对象

如果你在documents中只有一个或0个对象，就像你的例子一样，你可以使用reduce()和Object.keys()

var data = {"test1":{"documents":[]},"test2":{"documents":[{"vId":"sdfas23","TypeId":"81","isDeleted":false}],"answerswer":true},"test3":{"documents":[{"vId":"H1mJinyI","TypeId":"82","isDeleted":false}],"answerswer":true}}
var result = Object.keys(data).reduce(function(a, e) {
  if (data[e].documents[0]) a.push(data[e].documents[0].TypeId);
  return a;
}, [])
console.log(result)

对于documents数组中的多个对象，您可以将forEach循环添加到之前的代码中，以便您获得此(test3.documents中有两个对象)

var data = {"test1":{"documents":[]},"test2":{"documents":[{"vId":"sdfas23","TypeId":"81","isDeleted":false}],"answerswer":true},"test3":{"documents":[{"vId":"H1mJinyI","TypeId":"82","isDeleted":false},{"vId":"Random","TypeId":"100","isDeleted":false}],"answerswer":true}}
var result = Object.keys(data).reduce(function(a, e) {
  if (data[e].documents.length) data[e].documents.forEach(function(p) {
    a.push(p.TypeId);
  });
  return a;
}, [])
console.log(result);

只需一行代码:

_.map(_.flatten(_.map(_.values(data), 'documents')), 'TypeId');

这将产生:

["81", "82"]

这给了您预期的结果，尽管不确定您是否满意它

var data=  { 
    test1: { documents: [] },
    test2: { documents: [{ vId: 'sdfas23',
          TypeId: '81',
          isDeleted: false }], answer: true },
    test3:
     { documents:
        [{ vId: 'H1mJinyI',
          TypeId: '82',
          isDeleted: false }],
       answer: true } 
} 
function getIds(array) {
    var ret = [];
    for (key in data) {
        for (key2 in data[key].documents) {
            ret.push(data[key].documents[key2].TypeId)
         }
    }
    return ret
}
console.log(getIds(data));

你可以这样做:

1. 以一种方式访问每个对象，您可以为它使用相同的表达式。为…in将帮助您获取对象的键，您可以使用data[key]来获取对象。
2. 现在，一旦我们有了对象，我们知道在哪里看，即obj.documents。现在documents是一个数组，我们需要在其中的每个对象中获取TypeId。为此，你可以创建一个数组并手动向其中推送值，也可以使用array .map.
3. 现在如果你使用.map，它将为每个对象返回一个数组。因此，您必须使用array.concat将其附加到相同的函数。但是如果你使用.push，那么跳过这一步。

. .In + .map + .concat

var data={test1:{documents:[]},test2:{documents:[{vId:"sdfas23",TypeId:"81",isDeleted:!1}],answer:!0},test3:{documents:[{vId:"H1mJinyI",TypeId:"82",isDeleted:!1}],answer:!0}};
var r = [];
for(var k in data){
  r = r.concat(data[k].documents.map(function(o){return o.TypeId}));
}
console.log(r)

如果属性"documents"总是只有一个对象，只使用_.compact(_.map(data, 'documents[0].TypeId'));

如果属性"documents"有多个对象，使用_.flatten(_.map(data, (item) => _.map(item.documents, 'TypeId')));

示例- https://jsfiddle.net/qvkctvho/1/

这是前面答案的另一个简化版本(no reduce和fancy stuff only map):

var data=  { test1: { documents: [] },
             test2: { documents: [{ vId: 'sdfas23', TypeId: '81', isDeleted: false },{ vId: 'sdfas23', TypeId: '85', isDeleted: false }], answer: true },
             test3: { documents: [{ vId: 'H1mJinyI', TypeId: '82', isDeleted: false }], answer: true } 
};
var getTypeIds = function(data){
    var ids = [];
   // get object keys in this case : test1,test2,test3
    Object.keys(data).map(function(key){        
        // loop through each document attribute and extract TypeId attributes
        data[key].documents.map(function(item){                                                
                                    ids.push(item.TypeId);                                    
                                });

    })
    return ids;   
}
console.log(getTypeIds(data)); // [ '81', '85', '82' ]

试试这个

Object.getOwnPropertyNames(data).map(function(val, key) {    
    return data[val].documents[0] ? data[val].documents[0].TypeId : '';    
})

您可以使用_。lodash的映射函数以获得您想要的结果。下面是示例代码-

var result = _.map(data, function(v,i){
    if(_.isArray(v.documents)) {
        return v.documents[0].TypeId
    }
    return ''
}

在lodash中解决这个问题的最简单方法是使用flatMap()获得documents的扁平数组，并使用map()获得所有TypeId。

var result = _(data)
.flatMap('documents')
.map('TypeId')
.value();

var data = {
  test1: {
    documents: []
  },
  test2: {
    documents: [{
      vId: 'sdfas23',
      TypeId: '81',
      isDeleted: false
    }],
    answer: true
  },
  test3: {
    documents: [{
      vId: 'H1mJinyI',
      TypeId: '82',
      isDeleted: false
    }],
    answer: true
  }
};
var result = _(data)
.flatMap('documents')
.map('TypeId')
.value();
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.13.1/lodash.js"></script>

ES6的纯JS解决方案应该是这样的:

var result = Object.keys(data) // get keys as reference when mapping
.map(v => data[v].documents || []) // get all documents
.reduce((x, y) => x.concat(y)) // flatten
.map(v => v.TypeId); // get TypeId

var data = {
  test1: {
    documents: []
  },
  test2: {
    documents: [{
      vId: 'sdfas23',
      TypeId: '81',
      isDeleted: false
    }],
    answer: true
  },
  test3: {
    documents: [{
      vId: 'H1mJinyI',
      TypeId: '82',
      isDeleted: false
    }],
    answer: true
  }
};
var result = Object.keys(data)
.map(v => data[v].documents || [])
.reduce((x, y) => x.concat(y))
.map(v => v.TypeId);
console.log(result);