封装一些公共的接口方法函数仅供参考，只是自己的心得方便自己以后写项目直接用

// 日期格式化
//第一个参数是时间，第二个参数是转换出的结果什么样子
export function parseTime (time, pattern) {
  if (arguments.length === 0 || !time) {
    return null
  }
  const format = pattern || '{y}-{m}-{d} {h}:{i}:{s}'
  let date
  if (typeof time === 'object') {
    date = time
  } else {
    if ((typeof time === 'string') && (/^[0-9]+$/.test(time))) {
      time = parseInt(time)
    } else if (typeof time === 'string') {
      time = time.replace(new RegExp(/-/gm), '/');
    }
    if ((typeof time === 'number') && (time.toString().length === 10)) {
      time = time * 1000
    }
    date = new Date(time)
  }
  const formatObj = {
    y: date.getFullYear(),
    m: date.getMonth() + 1,
    d: date.getDate(),
    h: date.getHours(),
    i: date.getMinutes(),
    s: date.getSeconds(),
    a: date.getDay()
  }
  const time_str = format.replace(/{(y|m|d|h|i|s|a)+}/g, (result, key) => {
    let value = formatObj[key]
    // Note: getDay() returns 0 on Sunday
    if (key === 'a') { return ['日', '一', '二', '三', '四', '五', '六'][value] }
    if (result.length > 0 && value < 10) {
      value = '0' + value
    }
    return value || 0
  })
  return time_str
}

// 转换字符串，undefined,null等转化为""
export function praseStrEmpty (str) {
  if (!str || str == "undefined" || str == "null") {
    return "";
  }
  return str;
}

/**
 * 构造树型结构数据
 * @param {*} data 数据源
 * @param {*} id id字段 默认 'id'
 * @param {*} parentId 父节点字段 默认 'parentId'
 * @param {*} children 孩子节点字段 默认 'children'
 * @param {*} rootId 根Id 默认 0
 */
export function handleTree (data, id, parentId, children, rootId) {
  id = id || 'id'
  parentId = parentId || 'parentId'
  children = children || 'children'
  rootId = rootId || Math.min.apply(Math, data.map(item => { return item[parentId] })) || 0
  //对源数据深度克隆
  const cloneData = JSON.parse(JSON.stringify(data))
  //循环所有项
  const treeData = cloneData.filter(father => {
    let branchArr = cloneData.filter(child => {
      //返回每一项的子级数组
      return father[id] === child[parentId]
    });
    branchArr.length > 0 ? father.children = branchArr : '';
    //返回第一层
    return father[parentId] === rootId;
  });
  return treeData != '' ? treeData : data;
}