向数组 Ramda 插入一个新对象

Question

Ramda 有 insert function。但就我而言，我不知道如何钻取对象并将新对象插入到数组中。另外一个新对象应该在数组的最后一个索引上，我们可以通过 stuff["31"].length 获取它。我的尝试太可悲了，所以我决定不展示它们：/

数据模型：

const stuff = {
  "31": [
    {
      "id": "11",
      "title": "ramda heeeelp"
    },
    {
      "id": "12",
      "title": "ramda 123"
    },
    //HERE I WANT TO INSERT A NEW OBJECT - {id: "13", title: "new title"}
  ],
  "33": [
    {
      "id": "3",
      "title": "..."
    }
  ],
  "4321": [
    {
      "id": "1",
      "title": "hello world"
    }
  ]
}

Answer 1

这是对镜头的直接使用，append 加到最后。

我会这样做：

const addObjToGroup = (groupId, newObj, data) => 
  over (lensProp (groupId), append (newObj), data)

const stuff = {"31": [{"id": "11", "title": "ramda heeeelp"}, {"id": "12", "title": "ramda 123"}], "33": [{"id": "3", "title": "..."}], "4321": [{"id": "1", "title": "hello world"}]}

console .log (
  addObjToGroup ('31', {id: "13", title: "new title"}, stuff)
)

<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.26.1/ramda.js"></script>
<script>const {over, lensProp, append} = R                           </script>

Answer 2

您还可以使用 evolve 将项目附加到 groupId 中的数组：

const { evolve, append } = R

const addObjToGroup = (groupId, newObj) => evolve({ [groupId]: append(newObj) })

const stuff = {"31": [{"id": "11", "title": "ramda heeeelp"}, {"id": "12", "title": "ramda 123"}], "33": [{"id": "3", "title": "..."}], "4321": [{"id": "1", "title": "hello world"}]}

const result = addObjToGroup ('31', {id: "13", title: "new title"})(stuff)

console .log (result)

<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.26.1/ramda.js"></script>

Answer 3

也R.useWith在这里有帮助！

const appendTo = R.useWith(R.over, [
  R.lensProp,
  R.append,
  R.identity
]);


// ---
const stuff = {
  "31": [
    {
      "id": "11",
      "title": "ramda heeeelp"
    },
    {
      "id": "12",
      "title": "ramda 123"
    },
    //HERE I WANT TO INSERT A NEW OBJECT - {id: "13", title: "new title"}
  ],
  "33": [
    {
      "id": "3",
      "title": "..."
    }
  ],
  "4321": [
    {
      "id": "1",
      "title": "hello world"
    }
  ]
}

console.log(
  appendTo('31', 'HELLO WORLD', stuff),
);

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.26.1/ramda.js" integrity="sha256-xB25ljGZ7K2VXnq087unEnoVhvTosWWtqXB4tAtZmHU=" crossorigin="anonymous"></script>

向数组 Ramda 插入一个新对象

Insert a new object to array Ramda

javascript

functional-programming

object

ramda.js