树转数组的实现方法

//树形数据
const listTree = [
  {
    id: 1,
    name: '部门1',
    pid: 0,
    children: [
      {
        id: 2,
        name: '部门1-1',
        pid: 1,
        children: [
          {
            id: 4, 
            name: '部门1-1-1', 
            pid: 2,
            children: []
          }
        ]
      },
      {
        id: 3,
        name: '部门1-2',
        pid: 1,
        children: [
          {
            id: 5, 
            name: '部门1-2-1', 
            pid: 3,
            children: []
          }
        ]
      }
    ]
  },
  {
    id: 6,
    name: '部门2',
    pid: 0,
    children: [
      {
        id: 7, 
        name: '部门2-1', 
        pid: 6,
        children: []
      }
    ]
  },
  {
    id: 8,
    name: '部门3',
    pid: 0,
    children: []
  }
]

reduce取树行数据的所有子集

function treeTransList(tree, key) {
  return tree.reduce(function(con, item) {
    var callee = arguments.callee;
    con.push(item);
    if (item[key] && item[key].length >0)
      item[key].reduce(callee, con);
    return con;
  }, []).map(function(item){
    item[key] = [];
    return item;
  })
}
treeTransList(listTree, 'children')

递归实现

function getItem(tree, result) {
  for (let i = 0; i < tree.length; i++) {
    if(tree[i].children) {
      getItem(tree[i].children, result)
      delete tree[i].children;
    }
    result.push(tree[i])
  }
  return result;
}

function treeToList(tree) {
  const result = [];
  getItem(tree, result);
  return result;
}
treeToList(listTree)

广度优先遍历法

function treeToList(tree, childName = 'children') {
  // 设置临时数组，用来存放队列
  let queen = [];
  // 设置输出数组，用来存放要输出的一维数组
  const result = [];
  queen = queen.concat(tree);
  // 对树对象进行广度优先的遍历
  while(queen.length) {
    const first = queen.shift();
    if (first[childName]) {
      queen = queen.concat(first[childName]);
      delete first[childName]
    }
    result.push(first);
  }
  return result;
}  
treeToList(listTree, 'children')

实现效果

 [
  {id: 1, name: '部门1', pid: 0},
  {id: 2, name: '部门1-1', pid: 1},
  {id: 3, name: '部门1-2', pid: 1},
  {id: 4, name: '部门1-1-1', pid: 2},
  {id: 5, name: '部门1-2-1', pid: 3},
  {id: 6, name: '部门2', pid: 0},
  {id: 7, name: '部门2-1', pid: 6},
  {id: 8, name: '部门3', pid: 0},
]