常用算法

找出某个节点的所有父节点

var json = [
  {
    Id: '8797095327872057671',
    MenuName: 'Node1',
    Children: [
      {
        Id: '8797095327872057672',
        MenuName: 'Node2',
        Children: [
          {
            Id: '8797095327872057681',
            MenuName: 'Node3',
            Children: [
              {
                Id: '8797095327872057808',
                MenuName: 'Node4',
                Children: [],
              },
            ],
          },
        ],
      },
      {
        Id: '8797095327872057673',
        MenuName: 'Node5',
        Children: [],
      },
    ],
  },
]
function find(data, id, arr) {
  if (!arr) {
    arr = []
  }
  for (let index = 0; index < data.length; index++) {
    const element = data[index]
    if (element.Id == id) {
      //找到返回
      return arr
    }
    if (element.Children.length > 0) {
      if (find(element.Children, id, arr)) {
        arr.push(element.Id)
        //将父节点添加到arr，继续返回true
        return arr
      }
    }
  }
}
console.log(find(json, '8797095327872057808'))
//["8797095327872057681", "8797095327872057672", "8797095327872057671"]

简单格式的(pid)treeData 转复杂格式(children)

1

var arr = [
  {
    id: 1,
    parentid: 0,
  },
  {
    id: 4,
    parentid: 2,
  },
  {
    id: 3,
    parentid: 1,
  },
  {
    id: 5,
    parentid: 0,
  },
  {
    id: 6,
    parentid: 0,
  },
  {
    id: 2,
    parentid: 1,
  },
  {
    id: 7,
    parentid: 4,
  },
  {
    id: 8,
    parentid: 1,
  },
]
function unflatten(arr) {
  var tree = [],
    mappedArr = {},
    arrElem,
    mappedElem
  // First map the nodes of the array to an object -> create a hash table.
  for (var i = 0, len = arr.length; i < len; i++) {
    arrElem = arr[i]
    mappedArr[arrElem.id] = arrElem
    mappedArr[arrElem.id]['children'] = []
  }
  for (var id in mappedArr) {
    if (mappedArr.hasOwnProperty(id)) {
      mappedElem = mappedArr[id]
      // If the element is not at the root level, add it to its parent array of children.
      if (mappedElem.parentid) {
        mappedArr[mappedElem['parentid']]['children'].push(mappedElem)
      }
      // If the element is at the root level, add it to first level elements array.
      else {
        tree.push(mappedElem)
      }
    }
  }
  return tree
}
var tree = unflatten(arr)
console.log(tree)
document.body.innerHTML = '<pre>' + JSON.stringify(tree, null, ' ')

缺点：需要确认根节点。这个例子中，根节点是0

http://jsfiddle.net/alexandrupausan/qjxpLhfu/

2

var json = [
  {
    id: '105',
    pId: '13',
    name: '105',
  },
  {
    id: '1005',
    pId: '105',
    name: '1005',
  },
  {
    id: '10',
    pId: '1',
    name: '10',
  },
  {
    id: '1001',
    pId: '100',
    name: '1001',
  },
  {
    id: '10001',
    pId: '1001',
    name: '10001',
  },
  {
    id: '11',
    pId: '1',
    name: '11',
  },
  {
    id: '1000',
    pId: '100',
    name: '1000',
  },
  {
    id: '100',
    pId: '10',
    name: '100',
  },
  {
    id: '101',
    pId: '11',
    name: '101',
  },
  {
    id: '1002',
    pId: '101',
    name: '1002',
  },
  {
    id: '103',
    pId: '11',
    name: '102',
  },
  {
    id: '13',
    pId: '1',
    name: '13',
  },
]
function abc(obj, arr) {
  for (let j = 0; j < arr.length; j++) {
    const item = arr[j]
    if (obj.pId == item.id) {
      item.chriden = item.chriden || []
      item.chriden.push(obj)
      return true
    }
    if (item.chriden) {
      if (abc(obj, item.chriden)) {
        return true
      }
    }
  }
}
function test(arr) {
  for (let index = 0; index < arr.length; index++) {
    const element = arr[index]
    if (abc(element, arr)) {
      arr.splice(index, 1)
      test(arr)
      return
    }
  }
}
test(json)
console.log(json)
document.body.innerHTML = '<pre>' + JSON.stringify(json, null, '  ')

缺点：test每次从0开始，内部还有递归，会有无意义的递归