如何转换这种数据格式？

Question

头一次遇到 惭愧 竟然懵逼了无从下手。求大佬指点

var dataA = [
  { cid: 125, name: 'y1' },
  { cid: 845, name: 'y2' },
  { cid: 956, name: 'y3' },
  { cid: 634, name: 'y4' },
]

var dataB = [
  { uid: 984, name: 'x1' },
  { uid: 9634, name: 'x2' },
  { uid: 6574, name: 'x3' },
  { uid: 39764, name: 'x4' },
  { uid: 3164, name: 'x5' },
  { uid: 7421, name: 'x6' },
]

var dataC = [
  { id: 1245, cid: 125, uid: 984 },
  { id: 1237, cid: 845, uid: 3164 }
]


//期待数据 将上述三条数据转换成  如下
var corssData = [
  [
    'y1',
    { cid: 125, uid: 984, id: 1245, exist: true },
    { cid: 125, uid: 9634, id: null, exist: false },
    { cid: 125, uid: 6574, id: null, exist: false },
    { cid: 125, uid: 39764, id: null, exist: false },
    { cid: 125, uid: 3164, id: null, exist: false },
    { cid: 125, uid: 7412, id: null, exist: false },
  ],
  [
    'y2',
    { cid: 845, uid: 984, id: null, exist: false },
    { uid: 9634, cid: 125, id: null, exist: false },
    //...诸如此类
  ],
  // ...诸如此类
]

Answer 1

var corssData = dataA.map(iA => {
  return [iA.name, ...dataB.map(iB => {
    var c = dataC.find(iC => iC.cid === iA.cid && iC.uid === iB.uid)
    return {
     cid: iA.cid, uid: iB.uid, id: c && c.id, exist: !!c
    }
  })]
})

Answer 2

demo一个，写法上还可以再优化：

  var A = [
    { cid: 125, name: 'y1' },
    { cid: 845, name: 'y2' },
    { cid: 956, name: 'y3' },
    { cid: 634, name: 'y4' },
  ]

  var B = [
    { uid: 984, name: 'x1' },
    { uid: 9634, name: 'x2' },
    { uid: 6574, name: 'x3' },
    { uid: 39764, name: 'x4' },
    { uid: 3164, name: 'x5' },
    { uid: 7421, name: 'x6' },
  ]

  var C = [
    { id: 1245, cid: 125, uid: 984 },
    { id: 1237, cid: 845, uid: 3164 },
  ]

  var corssData = []

  function FunctionName (dataA, dataB, dataC) {
    dataA.forEach(function (item, index) {
      var array = []
      array.push(item.name)
      array.push(dataB.map(function (itemB, indexB) {
        var id = null
        var exist = false
        for (var i = 0; i < dataC.length; i++) {
          if (dataC[i].cid === item.cid && dataC[i].uid === itemB.uid) {
            id = dataC[i].id
            exist = true
          }
        }
        return {
          cid: item.cid,
          uid: itemB.uid,
          id: id,
          exist: exist,
        }
      }))
      corssData.push(array)
    })
  }

  FunctionName(A, B, C)
  console.log(corssData)