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通过扩展另一个数组对数组进行分组

arrays javascript

Vishal · 技术社区 · 7 年前

以前,我的数组的结构是:

[
  {
    "id": "Ddfwe23224533",
    "kind": "PEAK_EXPERIENCE",
    "title": "IP - Collective Identity",
  },
  {
    "id": "Ddfwe23224534",
    "kind": "PEAK_EXPERIENCE",
    "title": "IP - Collective Identity 2",
  },
  .....
]

我创建了一个名为flatToHierarchy的函数来对数组中的元素进行分组。代码如下:

export const flatToHierarchy = (arr, prop) => arr.reduce((accumulator, currentItem) => {
  const items = accumulator;
  const propValue = currentItem[prop];
  items[propValue] = items[propValue]
    ? [...items[propValue], currentItem]
    : [currentItem];
  return items;
}, {});

flatToHierarchy(elements, 'kind')

很好用。

[
  {
    "entity": {
      "id": "Ddfwe23224533",
      "kind": "PEAK_EXPERIENCE",
      "title": "IP - Collective Identity",
    },
    entity_id: "jj98834jfj983"
  },
  {
    "entity": {
      "id": "Ddfwe23224534",
      "kind": "PEAK_EXPERIENCE",
      "title": "IP - Collective Identity 2",
    },
    entity_id: "jj98834jfdf83"
  },
  .....
]

所以,对于按元素类型分组数组,我这样称呼它:

flatToHierarchy(elements, 'entity.kind')

现在,它给我的结果是:

{
  undefined: [....element1, ....element2 ]
}

{
  PEAK_EXPERIENCE: [....element1, ....element2 ]
}

我对此进行了深入研究,发现数组不能通过这种方式访问:

array['something.something']

需要通过以下方式访问:

array['something']['something']

所以,我改变了我的功能,但我卡住了。以下是我更改的函数:

export const flatToHierarchy = (arr, prop) => arr.reduce((accumulator, currentItem) => {
  const items = accumulator;
  const props = prop.split('.').map(p => [p]);
  console.log(props);
  const propValue = currentItem[prop];
  console.log(currentItem...props); // how to spread the array here?
  items[propValue] = items[propValue]
    ? [...items[propValue], currentItem]
    : [currentItem];
  return items;
}, {});

电流输入示例:

[
  {
    "entity": {
      "id": "Ddfwe23224533",
      "kind": "PEAK_EXPERIENCE",
      "title": "IP - Collective Identity",
    },
    entity_id: "jj98834jfj983"
  },
  {
    "entity": {
      "id": "Ddfwe23224534",
      "kind": "PEAK_EXPERIENCE",
      "title": "IP - Collective Identity 2",
    },
    entity_id: "jj98834jfdf83"
  },
  {
    "entity": {
      "id": "Ddfwe23224594",
      "kind": "PEAK_EXPERIENCE2",
      "title": "IP - Collective Identity 6",
    },
    entity_id: "jj98834jfdf33"
  },
]

所需输出示例:

{
  PEAK_EXPERIENCE: [
    {
      "entity": {
        "id": "Ddfwe23224533",
        "kind": "PEAK_EXPERIENCE",
        "title": "IP - Collective Identity",
      },
      entity_id: "jj98834jfj983"
    },
    {
      "entity": {
        "id": "Ddfwe23224534",
        "kind": "PEAK_EXPERIENCE",
        "title": "IP - Collective Identity 2",
      },
      entity_id: "jj98834jfdf83"
    },
  ],
  PEAK_EXPERIENCE2: [
    {
      "entity": {
        "id": "Ddfwe23224594",
        "kind": "PEAK_EXPERIENCE2",
        "title": "IP - Collective Identity 6",
      },
      entity_id: "jj98834jfdf33"
    },
  ],
}

更新2:

flatToHierarchy(array, string);

例子:

flatToHierarchy(elements, 'kind');

flatToHierarchy(elements, 'entity.kind');

2 回复 | 直到 7 年前

user3297291 7 年前

path 函数,可以使用 reduce 和初始对象的种子。

null / undefined

const propValue = prop
  .split('.') // Make a list of all property names (cannot contain a .)
  .reduce((obj, p) => obj[p], currentItem); // Loop over them to traverse your object

const flatToHierarchy = (arr, prop) => arr.reduce((accumulator, currentItem) => {
  const items = accumulator;
  const propValue = prop.split('.').reduce((obj, p) => obj[p], currentItem);
  items[propValue] = items[propValue]
    ? [...items[propValue], currentItem]
    : [currentItem];
  return items;
}, {});

const data = [
  {
    "entity": {
      "id": "Ddfwe23224533",
      "kind": "PEAK_EXPERIENCE",
      "title": "IP - Collective Identity",
    },
    entity_id: "jj98834jfj983"
  },
  {
    "entity": {
      "id": "Ddfwe23224534",
      "kind": "PEAK_EXPERIENCE",
      "title": "IP - Collective Identity 2",
    },
    entity_id: "jj98834jfdf83"
  },
  {
    "entity": {
      "id": "Ddfwe23224594",
      "kind": "PEAK_EXPERIENCE2",
      "title": "IP - Collective Identity 6",
    },
    entity_id: "jj98834jfdf33"
  },
]

console.log(
  flatToHierarchy(data, "entity.kind")
);

rmn 7 年前

考虑到您的示例输入是在一个名为数据

data = data.reduce((output, current) => {
    const kind = current.entity.kind
    output[kind] = (output[kind] || []).concat(current)
    return output
}, {})