从对象数组中获取重复对象

Question

我有这个初始数组，希望根据from.flightno和to.flightno提取重复航班

const myArray = [
        { from: { flightNo: 'A11' }, to: { flightNo: 'B11' }, code: 23 },
        { from: { flightNo: 'A12' }, to: { flightNo: 'B45' }, code: 22 },
        { from: { flightNo: 'A12' }, to: { flightNo: 'B52' }, code: 21 },
        { from: { flightNo: 'A11' }, to: { flightNo: 'B11' }, code: 20 },
        { from: { flightNo: 'A14' }, to: { flightNo: 'B44' }, code: 25 },
        { from: { flightNo: 'A15' }, to: { flightNo: 'B69' }, code: 24 },
        { from: { flightNo: 'A14' }, to: { flightNo: 'B44' }, code: 26 },
      ];

  result: 
 [
    { from: { flightNo: 'A11' }, to: { flightNo: 'B11' }, code: 23 },
    { from: { flightNo: 'A11' }, to: { flightNo: 'B11' }, code: 20 },
    { from: { flightNo: 'A14' }, to: { flightNo: 'B44' }, code: 25 },
    { from: { flightNo: 'A14' }, to: { flightNo: 'B44' }, code: 26 },
  ]

我写了这个，但我只能得到第一个重复的，看起来不是很漂亮。

  const duplicates = myArray
    .map((item) => {
      let count = 0;
      for (let i = 0; i < myArray.length; i++) {
        if (count > 1) {
          count = 0;
          return item;
        }
        if (
          myArray[i]?.from?.flightNo == item?.from?.flightNo &&
          myArray[i]?.to?.flightNo == item?.to?.flightNo
        )
          count++;
      }
    })
    .filter((notUndefined) => notUndefined !== undefined);

有什么建议吗？

Answer 1

您可以创建一个地图，通过航班号对（并使用json.stringify对该对进行字符串化）进行键控，每个键都有一个空数组。然后迭代数据以填充那些数组。

最后提取具有多个元素的子数组，并将结果平坦化：

null

const myArray = [{ from: { flightNo: 'A11' }, to: { flightNo: 'B11' }, code: 23 },{ from: { flightNo: 'A12' }, to: { flightNo: 'B45' }, code: 22 },{ from: { flightNo: 'A12' }, to: { flightNo: 'B52' }, code: 21 },{ from: { flightNo: 'A11' }, to: { flightNo: 'B11' }, code: 20 },{ from: { flightNo: 'A14' }, to: { flightNo: 'B44' }, code: 25 },{ from: { flightNo: 'A15' }, to: { flightNo: 'B69' }, code: 24 },{ from: { flightNo: 'A14' }, to: { flightNo: 'B44' }, code: 26 },];

let map = new Map(myArray.map(o => [JSON.stringify([o.from.flightNo, o.to.flightNo]), []]));
for (let o of myArray) map.get(JSON.stringify([o.from.flightNo, o.to.flightNo])).push(o);
let result = [...map.values()].filter(arr => arr.length > 1).flat();

console.log(result);