在一系列对象中获取第一个重复项JavaScript

Question

我有以下我从API中获得的数据结构：

[
  {
    id: '10000844',
    text_id: '10000844-01',
  },
  {
    id: '10000844',
    text_id: '10000844-02',
  },
  {
    id: '12000844',
    text_id: '12000844-03',
  },
  {
    id: '12000844',
    text_id: '12000844-07',
  },
  {
    id: '12000814',
    text_id: '12000844-07',
  },
 {
    id: '12002812',
    text_id: '12000844-07',
  },
   {
    id: '12000814',
    text_id: '12000844-08',
  },
]

清洁代码的完美结果将是此结果，基本上仅返回第一个发现的ID：

[
      {
        id: '10000844',
        text_id: '10000844-01',
      },
      {
        id: '12000844',
        text_id: '12000844-03',
      },
      {
        id: '12000814',
        text_id: '12000844-07',
      },
     {
        id: '12002812',
        text_id: '12000844-07',
      },
    ]

但是当前它仅返回最后发现的副本，以唯一的数组，而当前代码：

let uniqueArray = [...new Map(data.map(item =>
    [item.id, item])).values()];

Answer 1

您可以使用object.values（）和redion（）与：

const data = [
  {
    id: '10000844',
    text_id: '10000844-01',
  },
  {
    id: '10000844',
    text_id: '10000844-02',
  },
  {
    id: '12000844',
    text_id: '12000844-03',
  },
  {
    id: '12000844',
    text_id: '12000844-07',
  },
  {
    id: '12000814',
    text_id: '12000844-07',
  },
 {
    id: '12002812',
    text_id: '12000844-07',
  },
   {
    id: '12000814',
    text_id: '12000844-08',
  },
]

const result = Object.values(
  data.reduce((res, {id, text_id}) => {
    res[id] ??= {id, text_id}
    return res
  }, {})
)
console.log(result)

更新带有?? = 文档

逻辑无效分配（x ?? = y）操作员仅分配如果x为nullish（nullish或null或Undefined）。

Answer 2

您可以这样做：

const arr = [
  {
    id: '10000844',
    text_id: '10000844-01',
  },
  {
    id: '10000844',
    text_id: '10000844-02',
  },
  {
    id: '12000844',
    text_id: '12000844-03',
  },
  {
    id: '12000844',
    text_id: '12000844-07',
  },
  {
    id: '12000814',
    text_id: '12000844-07',
  },
 {
    id: '12002812',
    text_id: '12000844-07',
  },
   {
    id: '12000814',
    text_id: '12000844-08',
  },
];
const unique = [];
const visited = new Set();
for(let i = 0; i < arr.length; ++i){
  if(!visited.has(arr[i].id)){
    unique.push(arr[i]);
    visited.add(arr[i].id);
  }
}

console.log(unique);

Answer 3

概念

循环通过数据中的所有对象，并检查结果数组中是否找到ID。如果找不到，请将其推入结果数组；否则，请跳过。

代码

const data = [{
    id: '10000844',
    text_id: '10000844-01',
  },
  {
    id: '10000844',
    text_id: '10000844-02',
  },
  {
    id: '12000844',
    text_id: '12000844-03',
  },
  {
    id: '12000844',
    text_id: '12000844-07',
  },
  {
    id: '12000814',
    text_id: '12000844-07',
  },
  {
    id: '12002812',
    text_id: '12000844-07',
  },
  {
    id: '12000814',
    text_id: '12000844-08',
  },
];
let result = [];
let found;
data.forEach(d => {
  found = false;
  result.forEach(r => {
    if (!found && r.id === d.id) found = true;
  })
  if (!found) result.push(d);
});
console.log(result);

Answer 4

这是实现您渴望输出的另一种方法。
我们使用REDY用于更改数据并使用查找函数以获取当前ID是否已在prev> prev中是否存在不是然后，我们使用filter函数来滤除相同的id对象，然后首先按下。

const data =[
  {
    id: '10000844',
    text_id: '10000844-01',
  },
  {
    id: '10000844',
    text_id: '10000844-02',
  },
  {
    id: '12000844',
    text_id: '12000844-03',
  },
  {
    id: '12000844',
    text_id: '12000844-07',
  },
  {
    id: '12000814',
    text_id: '12000844-07',
  },
 {
    id: '12002812',
    text_id: '12000844-07',
  },
   {
    id: '12000814',
    text_id: '12000844-08',
  },
]

const newData = data.reduce((prev, curr, index, arr) => {
  const find = prev.find(p => p.id === curr.id);
  if (!find) {
    const filter = arr.filter(f => f.id === curr.id);
    if (filter.length >= 1) {
      prev.push(filter[0])
    }
  }
  return prev;
}, [])

console.log(newData)

Answer 5

您可以 阵列中仅存储每个ID首次出现的对象，然后提取 values 来自此对象。

const 
  data = [{ id: "10000844", text_id: "10000844-01" }, { id: "10000844", text_id: "10000844-02" }, { id: "12000844", text_id: "12000844-03" }, { id: "12000844", text_id: "12000844-07" }, { id: "12000814", text_id: "12000844-07" }, { id: "12002812", text_id: "12000844-07" }, { id: "12000814", text_id: "12000844-08" }],
  result = Object.values(data.reduce((acc, d) => (!acc[d.id] ? { ...acc, [d.id]: d } : acc), {}));

console.log(result);

Answer 6

一些答案已经正确。

此答案仅在您使用lodash 时才

可以使用 uniqby 。

这将返回一个阵列的无重复版本，其中第一次出现将保留一个阵列：

因此，在您的情况下，

import uniqBy from 'lodash/uniqBy';

// dataFromAPI is your sample data
const unqiueArray = uniqBy(dataFromAPI, 'id');

Answer 7

有时

1. 创建一个临时对象
2. 如果找不到其键，则在数据上添加对象的数据，
3. 。获取输出对象的值

const data=[{id:"10000844",text_id:"10000844-01"},{id:"10000844",text_id:"10000844-02"},{id:"12000844",text_id:"12000844-03"},{id:"12000844",text_id:"12000844-07"},{id:"12000814",text_id:"12000844-07"},{id:"12002812",text_id:"12000844-07"},{id:"12000814",text_id:"12000844-08"}];

// Initialise the output object
const out = {};

// Loop over the array of objects
for (const obj of data) {

  // For each object destructure the id from the rest
  // of its properties 
  const { id, ...rest } = obj;

  // If there is no property on the output
  // object with that key create it by adding
  // an object composed of the id and the other
  // object properties to it
  out[id] ??= { id, ...rest };
}

// Now return an array of
// the output object's values
console.log(Object.values(out));

附加文档

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