javascript - 嵌套在 JSON 对象数组中的 JSON 对象数组

Question

我有一个格式为 JSON 的对象数组

var employees = 
[
  {
    "employee1": "employee1",
    "Details": [
      {
        "title": "Software Engineer",
        "EmployeeId": 451
      }
    ]
  },
  {
    "employee2": "employee2",
    "Details": []
  },
  {
    "employee3": "employee3",
    "Details": [
      {
        "title": "Test analyst",
        "EmployeeId": 453
      }
    ]
  },
  {
    "employee4": "employee4",
    "Details": [
      {
        "title": "Software engineer",
        "EmployeeId": 487
      },
      {
        "title": "Architect",
        "EmployeeId": 500
      }
    ]
  }
]

获取 EmployeeId 的最佳方式是什么？

预期输出:

[451,453,487,500]

当我使用:

console.log(Object.assign({}, ...employees).Details.map(t=>t.EmployeeId))

返回结果为:

[487,500]

有没有办法在结果中连接其他员工 ID？

Answer 1

首先 - 它不是 JSON，只是一个数组。其次，像这样使用 flatMap 和 map:

var employees = [{
    "employee1": "employee1",
    "Details": [{
      "title": "Software Engineer",
      "EmployeeId": 451
    }]
  },
  {
    "employee2": "employee2",
    "Details": []
  },
  {
    "employee3": "employee3",
    "Details": [{
      "title": "Test analyst",
      "EmployeeId": 453
    }]
  },
  {
    "employee4": "employee4",
    "Details": [{
        "title": "Software engineer",
        "EmployeeId": 487
      },
      {
        "title": "Architect",
        "EmployeeId": 500
      }
    ]
  }
];

var ids = employees.flatMap(({ Details }) => Details.map(({ EmployeeId }) => EmployeeId));

console.log(ids);

没有 flatMap 的 Polyfill - 由 MDN's alternative 提供:

var employees = [{
    "employee1": "employee1",
    "Details": [{
      "title": "Software Engineer",
      "EmployeeId": 451
    }]
  },
  {
    "employee2": "employee2",
    "Details": []
  },
  {
    "employee3": "employee3",
    "Details": [{
      "title": "Test analyst",
      "EmployeeId": 453
    }]
  },
  {
    "employee4": "employee4",
    "Details": [{
        "title": "Software engineer",
        "EmployeeId": 487
      },
      {
        "title": "Architect",
        "EmployeeId": 500
      }
    ]
  }
];

var ids = employees.reduce((acc, { Details }) => acc.concat(Details.map(({ EmployeeId }) => EmployeeId)), []);

console.log(ids);