javascript - 如何使用 lodash 将两个数组(数组 1d 和数组 2d 对象)合并为数组

Question

我正在寻找做到这一点的最佳方法。我有两个数组(数组 1d 和数组 2d 对象):

let keys = [11, 12];
let values = [
[
   { name: '1', link: '1', history: '1' },
   { name: '2', link: '2', history: '2' }
 ],
 [
   { name: '3', link: '3', history: '3' },
   { name: '4', link: '4', history: '4' }
 ]
]

我想要的最终结果是一个 map 数组:

[
   { name: '1', link: '1', history: '1' , q : 11},
   { name: '2', link: '2', history: '2' , q : 11},
   { name: '3', link: '3', history: '3' , q : 12},
   { name: '4', link: '4', history: '4' , q : 12}
]

如何使用 lodash 以最有效/最干净的方式做到这一点？谢谢!

This code without lodash :

let arr = [];
let keys = [ 29, 30 ]
let values = [
  [
    { name: '1', link: '1', history: '1' },
    { name: '2', link: '2', history: '2' }
  ],
  [
    { name: '3', link: '3', history: '3' },
    { name: '4', link: '4', history: '4' }
  ]
]
for (let j = 0; j < values.length; j++) {
  for (let i = 0; i < values[j].length; i++) {
    arr.push({ ...values[j][i], q: keys[j] });
  }
}
console.log(arr)

Answer 1

你可以简单地使用_.map

let keys = [11, 12];
let values = [[{"name":"1","link":"1","history":"1"},{"name":"2","link":"2","history":"2"}],[{"name":"3","link":"3","history":"3"},{"name":"4","link":"4","history":"4"}]]
console.log(_.map(values, (v, i) => _.map(v, o => (o.q = keys[i], o))))

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.core.js"></script>

或者没有 lodash，语法几乎相同

let keys = [11, 12];
let values = [[{"name":"1","link":"1","history":"1"},{"name":"2","link":"2","history":"2"}],[{"name":"3","link":"3","history":"3"},{"name":"4","link":"4","history":"4"}]]
console.log(values.map((v, i) => v.map(o => (o.q = keys[i], o))))

编辑:我忘记了结果数组必须是一维的。 - lodash 变体需要对结果进行一些 _.flatten - 原生js需要.flat()

最后可以使用 lodash/fp 来获得一些链接样式

let keys = [11, 12];
let values = [[{"name":"1","link":"1","history":"1"},{"name":"2","link":"2","history":"2"}],[{"name":"3","link":"3","history":"3"},{"name":"4","link":"4","history":"4"}]]

console.log(
  _.flow(
    // we need to use entries to get the index of fp.map
    _.entries,
    // for each array
    _.map(([i, v]) => 
      // foreach "history" of the array
      _.map(
        // merge the key to the current "history"
        _.merge({ q: keys[i] }), v)
      ),
    _.flatten
  )(values)
)

console.log(
  _.flow(
    // or its variant
    _.map.convert({ cap: false })((v,i) => _.map(_.merge({ q: keys[i] }), v)),
    _.flatten
  )(values)
)

<script src="https://cdn.jsdelivr.net/g/lodash@4(lodash.min.js+lodash.fp.min.js"></script>