使用 reduce 转换一个 js 对象

Question

我想写一个函数来传递这个对象

[
  {
    "id": "656DDXFT565xX",
    "name": "Black item",
    "categorues": [
      "Black",
      "White"
    ],
    "price": 5
  }
]

成为那样的人

[
    {
        "Black": [
            {
                "id": "656DDXFT565xX",
                "name": "Black item",
                "categories": [
                    "Black",
                    "White"
                ],
                "price": 5
            }
        ]
    },
    {
        "White": [
            {
                "id": "656DDXFT565xX",
                "name": "Black item",
                "categories": [
                    "Black",
                    "White"
                ],
                "price": 5
            }
        ]
    }
]

我试过 Array.reduce，但我不知道如何渲染它。

如果有人对此有任何后见之明

Answer 1

let before = [
  {
    "id": "656DDXFT565xX-BW",
    "name": "Black and white item",
    "categories": [
      "Black",
      "White"
    ],
    "price": 5
  },
  {
    "id": "656DDXFT565xX-K",
    "name": "Black item",
    "categories": [
      "Black"
    ],
    "price": 10
  },
  {
    "id": "656DDXFT565xX-W",
    "name": "White item",
    "categories": [
      "White"
    ],
    "price": 15
  }
]

let after = before.reduce(
  (acc, val) => {
    val.categories.forEach(cat => {
      acc[cat] ||= [] 
      // if this fails, use newer version of node, or use
      // if(!acc.cat) acc.cat = []
      
      acc[cat].push(val)
    })
    return acc
  },
  {}
)

console.log(after)

Answer 2

您可以使用 .map 遍历每个项目的 categorues 以获得预期结果。这是一个使用 lodash:

的解决方案

const data = [
  { "id":"656DDXFT565xX", "name":"Colored item", "categorues":["Black","White"], "price":5 },
  { "id":"656DDXFT565x2", "name":"White item", "categorues":["White"], "price":5 },
  { "id":"656DDXFT565x3", "name":"Black item", "categorues":["Black"], "price":5 }
];

const _reduceElem = (elem={}) => {
  const { categorues=[] } = elem;
  return _.map( categorues, cat => ({ [cat]: [_.cloneDeep(elem)] }) );
}
const res = _.reduce(data, (acc,item) => {
  acc = [...acc, ..._reduceElem(item)];
  return acc;
}, []);

console.log(res);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js" integrity="sha512-WFN04846sdKMIP5LKNphMaWzU7YpMyCU245etK3g/2ARYbPK9Ub18eG+ljU96qKRCWh+quCY7yefSmlkQw1ANQ==" crossorigin="anonymous"></script>

Answer 3

因为您只想提取 categorues 作为密钥。您不需要使用 reduce，只需使用 map 循环 categorues 即可。

const origin = [
  {
    "id": "656DDXFT565xX",
    "name": "Black item",
    "categorues": [
      "Black",
      "White"
    ],
    "price": 5
  }
]

const categorues = origin[0].categorues;
const result = categorues.map(item => {
  return {
    [item]: origin
  }
})

console.log(result)

使用 reduce 转换一个 js 对象

transform a js object using reduce

javascript

arrays

reduce