How to realize the reorganization of arrays gracefully

classify and reorganize according to the value of a field

Source data: 

var _arr = [{
    aId: 1,
    bId: 11,
    cId: 112,
}, {
    aId: 1,
    bId: 11,
    cId: 113,
}, {
    aId: 1,
    bId: 12,
    cId: 114,
}, {
    aId: 2,
    bId: 21,
    cId: 211,
}]

expectation: 

[{
    aId: 1,
    children: [{
        bId: 11,
        children: [{
            cId: 112
        }, {
            cId: 113
        }]
    }, {
        bId: 12,
        children: [{
            cId: 114
        }]
    }]
}, {
    aId: 2,
    children: [{
        bId: 21,
        children: [{
            cId: 211
        }]
    }]
}]
Javascript
Jun.03,2021 
function trans (arr, keys) {
  let result = []
  let keyToRef = {}
  let len = keys.length
  arr.forEach(cur => {
    let obj
    let cacheKey = ''
    for (let i = 0; i < len; iPP) {
      let key = keys[i]
      cacheKey += key + cur[key]
      let ref = keyToRef[cacheKey]
      if (ref) {
        obj = ref
      } else {
        ref = i === 0 ? result : obj.children ? obj.children : obj.children = []
        obj = {
          [key]: cur[key]
        }
        keyToRef[cacheKey] = obj
        ref.push(obj)
      }
    }
  })
  return result
}
trans(_arr, ['aId', 'bId', 'cId'])
function rebuild (arr, key) {
  let res = []
  let keycopy = JSON.parse(JSON.stringify(key))
  let k = keycopy.shift()
  while (arr.length) {
    let obj = {}
    obj[k] = arr[0][k]
    let arrcopy = JSON.parse(JSON.stringify(arr))
    obj.children = arrcopy.filter(val => val[k] === obj[k]).map(val => {
      delete val[k]
      return val
    })
    res.push(obj)
    arr = arr.filter(val => val[k] !== obj[k])
  }
  return res.map(val => keycopy.length ? {
    ...val,
    children: rebuild(val.children, keycopy)
  } : val)
}
rebuild(_arr,['aId','bId'])

Previous: Element-ui calculates the date range

Next: Websocket is under https, is it necessary to use wss protocol to connect?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
© 2021 CodesHelper
Advertising Contact us About us
Menu