js 数组对象处理

Question

[
{backupType: "全备", weekCycle: 1, weekDay: 0, sequenceNumber: 1}
{backupType: "全备", weekCycle: 1, weekDay: 0, sequenceNumber: 2}
{backupType: "全备", weekCycle: 1, weekDay: 1, sequenceNumber: 2}
{backupType: "全备", weekCycle: 1, weekDay: 2, sequenceNumber: 3}
{backupType: "全备", weekCycle: 1, weekDay: 3, sequenceNumber: 3}
{backupType: "全备", weekCycle: 1, weekDay: 6, sequenceNumber: 3}
]

根据sequenceNumber，将数组分为三个部分，sequenceNumber一致的放在一块
如

[
{backupType: "全备", weekCycle: 1, weekDay: 0, sequenceNumber: 1}
{backupType: "全备", weekCycle: 1, weekDay: [0,1], sequenceNumber: 2}
{backupType: "全备", weekCycle: 1, weekDay: [2,3,6], sequenceNumber: 3}
]

Answer 1

let data = [
  {backupType: "全备", weekCycle: 1, weekDay: 0, sequenceNumber: 1},
  {backupType: "全备", weekCycle: 1, weekDay: 0, sequenceNumber: 2},
  {backupType: "全备", weekCycle: 1, weekDay: 1, sequenceNumber: 2},
  {backupType: "全备", weekCycle: 1, weekDay: 2, sequenceNumber: 3},
  {backupType: "全备", weekCycle: 1, weekDay: 3, sequenceNumber: 3},
  {backupType: "全备", weekCycle: 1, weekDay: 6, sequenceNumber: 3}
]

let cache = {}
data = data.filter(item => {
  let num = item.sequenceNumber
  let weekDay = item.weekDay
  let tmp = cache[num]

  if (tmp) {
    let tmpWeekDay = tmp.weekDay
    if (Array.isArray(tmpWeekDay)) {
      tmpWeekDay.push(weekDay)
    } else {
      tmp.weekDay = [tmpWeekDay, weekDay]
    }
    return false
  } else {
    cache[num] = item
    return true
  }
})

Answer 2

我的思路：循环两次，外层拿到的对象作为参照对象，和内层循环到的对象依次做对比，找到一样的就拿到它的weekDay值push给参照对象，然后删除掉。

因为初始weekDay是number型，找到之后还要转换成数组才行。

    var arr = [
        { weekDay: 0, sequenceNumber: 1 }, 
        { weekDay: 0, sequenceNumber: 2 }, 
        { weekDay: 1, sequenceNumber: 2 }, 
        { weekDay: 2, sequenceNumber: 3 }, 
        { weekDay: 3, sequenceNumber: 3 }, 
        { weekDay: 6, sequenceNumber: 3 }
    ];
    for(let i = 0; i < arr.length; i++) {
        arr.map((m, n) => {
            if (arr[i].sequenceNumber === m.sequenceNumber && i !== n) {
                // 将参照对象的weekDay转换成数组
                arr[i].weekDay = [arr[i].weekDay]
                // 将该对象的weekDay值push到参照对象中，并删除
                arr[i].weekDay.push(m.weekDay)
                arr.splice(n, 1)
            }
        })
    }
    
    console.log(arr)

Answer 3

arr1=arr.filter((entity)=>{entity.sequenceNumber==1});
arr2=....
以此类推，不写了

Answer 4

遍历数组，然后根据sequenceNumber的值push到不同的数组里面。