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是否可以使用lodash更新嵌套对象的特定值?

lodash recursion javascript

Thidasa Pankaja · 技术社区 · 3 年前

我有一个像这样的嵌套对象

let obj = {
  id: "XXX",
  children: [
    {
      id: "YYY",
      children: [],
      path: ["XXX", "YYY"],
      type: "text"
    },
    {
      id: "ZZZ",
      children: [],
      path: ["XXX", "ZZZ"],
      type: "button"
    }
  ],
  path: ["XXX"],
  type: "row"
};

我需要循环浏览所有儿童并更新路径通过附加一个字符串数组 const newPath = ["A", "B", "C"];

let newObj = cloneDeepWith(obj, (node) => {
  if (node.id) {
    node = { ...node, path: [...newPath, ...node.path] };
    console.log("updated : ", node)
  }
});

所以更新对象的最终输出应该是

let obj = {
  id: "XXX",
  children: [
    {
      id: "YYY",
      children: [],
      path: ["A", "B", "C", "XXX", "YYY"],
      type: "text"
    },
    {
      id: "ZZZ",
      children: [],
      path: ["A", "B", "C", "XXX", "ZZZ"],
      type: "button"
    }
  ],
  path: ["A", "B", "C", "XXX"],
  type: "row"
};

我正试图用lodash中的cloneDeepWith函数这样做

let updatedObj = cloneDeepWith(obj, (node) => {
  if (node.id) {
    node = { ...node, path: [...newPath, ...node.path] };
    console.log("updated : ", node)
  }
});

在每个console.log中,它都会打印更正后的更新节点(在本例中为3,带有父节点),但不会返回 updatedObj

我怎样才能做到这一点?

2 回复 | 直到 3 年前

Keith 3 年前

我不知道该怎么做 lodash ,但使用纯JS做这件事相当容易。你的 recursion 标签是关键。。

如。

let obj = {
  id: "XXX",
  children: [
    {
      id: "YYY",
      children: [],
      path: ["XXX", "YYY"],
      type: "text"
    },
    {
      id: "ZZZ",
      children: [],
      path: ["XXX", "ZZZ"],
      type: "button"
    }
  ],
  path: ["XXX"],
  type: "row"
};

function addABC(obj) {
  if (obj.path) obj.path = ['A','B','C',...obj.path];
  if (obj.children) for (const s of obj.children) addABC(s);
}

addABC(obj);

console.log(obj);

Nenad Vracar 3 年前

您可以使用Lodash来完成此操作 cloneDeepWith 方法,但在这种情况下,它也会修改原始数据。

let obj = {
  id: "XXX",
  children: [{
      id: "YYY",
      children: [],
      path: ["XXX", "YYY"],
      type: "text"
    },
    {
      id: "ZZZ",
      children: [],
      path: ["XXX", "ZZZ"],
      type: "button"
    }
  ],
  path: ["XXX"],
  type: "row"
};

const newPath = ["A", "B", "C"];

const clone = _.cloneDeepWith(obj, value => {
  if (_.isArray(value.path)) {
    value.path = [...newPath, ...value.path]
  }
})

console.log(clone)

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js"></script>

Scott Sauyet 3 年前

没有库的不可变方法可能是这样的:

const prependPaths = (prefix) => ({path, children, ...rest}) => ({
  ...rest,
  path: [...prefix, ...path],
  children: children .map (prependPaths (prefix))
})

const obj = {id: "XXX", children: [{id: "YYY", children: [], path: ["XXX", "YYY"], type: "text"}, {id: "ZZZ", children: [], path: ["XXX", "ZZZ"], type: "button"}], path: ["XXX"], type: "row"}

console .log (prependPaths (['A', 'B', 'C']) (obj))

.as-console-wrapper {max-height: 100% !important; top: 0}

这是一个简单的递归,其中我们 map 使用我们的函数,通过预配置 prefix 参数(此处, ['A', 'B', 'C'] .)

但请注意,您的物品 path 节点携带一些冗余信息,这些信息可以从id的层次结构中派生,如果您有一个不包含这些信息的原始表单 路径 节点,您仍然可以通过大约相同的努力实现相同的效果:

const addPaths = (prefix = []) => ({id, children, ...rest}) => ({
  id,
  ...rest,
  path: [...prefix, id],
  children: children .map (addPaths ([...prefix, id]))
})

// No `path` nodes here.
const obj2 = {id: "XXX", children: [{id: "YYY", children: [], type: "text"}, {id: "ZZZ", children: [], type: "button"}], type: "row"}

// But the output includes the correct full paths.
console .log (addPaths (['A', 'B', 'C']) (obj2))

.作为控制台包装{最大高度:100%!重要;顶部:0}

主要区别在于递归调用采用前缀的更新版本,添加 id 当前对象的。