Question

说我有一个看起来像这样的对象：

{
  "data": {
    "postsConnection": {
      "groupBy": {
        "author": [
          {
            "key": "xyz",
            "connection": {
              "aggregate": {
                "count": 5
              }
            }
          },
          {
            "key": "abc",
            "connection": {
              "aggregate": {
                "count": 3
              }
            }
          }
        ]
      }
    }
  }
}

一个人如何访问与count作为其关键字的author元素对应的xyz的值？我知道对于这个特定的示例，我可以这样做：

const n = data.postsConnection.groupBy.author[0].connection.aggregate.count

但这意味着要事先知道数组中的哪个元素拥有key的期望值，在我的上下文中情况并非如此。

Answer 1

如果作者可以出现多次，则可以.filter()存储在author的数组，然后将.map()的结果保存到count：

const data = {data:{postsConnection:{groupBy:{author:[{key:"xyz",connection:{aggregate:{count:5}}},{key:"abc",connection:{aggregate:{count:3}}}]}}}};

const author = "xyz";
const res = data.data.postsConnection.groupBy.author.filter(({key}) => key === author).map(obj => obj.connection.aggregate.count);

console.log(res);

// If you want to get the total of all counts for the given author, you can use reduce on the result to sum:
const totalCountsForAuthor = res.reduce((acc, n) => acc+n, 0);
console.log(totalCountsForAuthor);

如果作者只能出现一次，则可以使用.find()代替.filter()，如下所示：

const data = {data:{postsConnection:{groupBy:{author:[{key:"xyz",connection:{aggregate:{count:5}}},{key:"abc",connection:{aggregate:{count:3}}}]}}}};

const author = "xyz";
const res = data.data.postsConnection.groupBy.author.find(({key}) => key === author).connection.aggregate.count

console.log(res);

Answer 2

您可以使用Array#find获取满足特定条件的数组中的第一个实例（在您的情况下，您的key值等于key值的第一个实例）想要）。

var obj = {"data":{"postsConnection":{"groupBy":{"author":[{"key":"xyz","connection":{"aggregate":{"count":5}}},{"key":"abc","connection":{"aggregate":{"count":3}}}]}}}};

function getAuthorByKey(key) {
  return obj.data.postsConnection.groupBy.author.find(author => author.key === key);
}

console.log(getAuthorByKey("xyz").connection.aggregate.count);
console.log(getAuthorByKey("abc").connection.aggregate.count);

Answer 3

如果author数组始终存在：

const data = {
      postsConnection: {
          groupBy: {
              author: [{
                  key: "xyz",
                  connection: {
                      aggregate: {
                          count: 5
                      }
                  }
              }, {
                  key: "abc",
                  connection: {
                      aggregate: {
                          count: 3
                      }
                  }
              }]
          }
      }
};

function getCount(keyVal) {
    const element = data.postsConnection.groupBy.author.find(item => item.key === keyVal)
    return element.connection.aggregate.count || "";
}

console.log(getCount('xyz'))

Answer 4

var data = { "data": {
    "postsConnection": {
      "groupBy": {
        "author": [
          {
            "key": "xyz",
            "connection": {
              "aggregate": {
                "count": 5
              }
            }
          },
          {
            "key": "abc",
            "connection": {
              "aggregate": {
                "count": 3
              }
            }
          }
        ]
      }
    }
  }
  };
  
  data.data.postsConnection.groupBy.author.forEach((autor) => {
  if(autor.key === "xyz")
    console.log(autor.connection.aggregate);
  });

Answer 5

您可以利用数组查找，通过“键”查找作者。

文档：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find

const author = data.postsConnection.groupBy.author.find((author) => author.key === "xyz")

CodePen： https://codepen.io/gmaslic/pen/wvwbLoL

然后，您可以访问找到的“作者”中的所有属性

如何通过其键之一的值访问嵌套在数组内的对象？

5 个答案: