如何使用 Lodash 在 javascript 中按键合并对象

Question

我有这个对象数组：

[
  {
    id: 1, oid: 5, 
    dates: { 
      5: {start_date: "12.30", end_date: "12.31" },
      14: {start_date: "01.01", end_date: "01.15" }
    }
  },
  {
    id: 2, oid: 5, 
    dates: { 
      17: {start_date: "02.01", end_date: "02.20" },
      19: {start_date: "03.01", end_date: "03.10" }
    }
  }
]

如何通过“日期”键合并并用 Lodash 得到这个结果

{
  5: {start_date: "12.30", end_date: "12.31" },
  14: {start_date: "01.01", end_date: "01.15" },
  17: {start_date: "02.01", end_date: "02.20" },
  19: {start_date: "03.01", end_date: "03.10" }
}

Answer 1

 const output = input.reduce((res, {dates}) => res.concat(dates), []);

您可以使用reduce 来迭代对象并使用concat 一起迭代结果。根本不需要使用 loadash。

Answer 2

使用 Lodash

您可以使用_.map() 来获取日期对象的数组。要将对象合并为一个，将使用_.merge()。我们将使用_.partial() 添加一个目标对象，因此我们不会改变原始数据。此外，我们将在_.merge() 上使用_.spread() 方法，因此它可以处理对象数组：

var data = [{"id":1,"oid":5,"dates":{"5":{"start_date":"12.30","end_date":"12.31"},"14":{"start_date":"01.01","end_date":"01.15"}}},{"id":2,"oid":5,"dates":{"17":{"start_date":"02.01","end_date":"02.20"},"19":{"start_date":"03.01","end_date":"03.10"}}}];


var result = _.spread(_.partial(_.merge, {}))(_.map(data, 'dates'));

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

使用 ES6

在Object#keys 上使用Array#map 提取dates，然后通过spreading 将Object.assign 压平为Object.assign：

var data = [{"id":1,"oid":5,"dates":{"5":{"start_date":"12.30","end_date":"12.31"},"14":{"start_date":"01.01","end_date":"01.15"}}},{"id":2,"oid":5,"dates":{"17":{"start_date":"02.01","end_date":"02.20"},"19":{"start_date":"03.01","end_date":"03.10"}}}];

var result = Object.assign({}, ...Object.keys(data).map((key) => data[key].dates));

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

Answer 3

使用 lodash，您可以首先使用 spread operator map 日期和 assign 一起使用 spread operator：

let result = _.assign({}, ..._.map(data, 'dates'))