js树结构扁平化

  /**
     *
     * @param {Array} arrs 树形数据
     * @param {string} childs 树形数据子数据的属性名,常用'children'
     * @param {Array} attrArr 需要提取的公共属性数组(默认是除了childs的全部属性)
     * @returns
     */
    extractTree(arrs, childs = 'children', attrArr) {
      let attrList = []
      if (!Array.isArray(arrs) && !arrs.length) return []
      if (typeof childs !== 'string') return []
      if (!Array.isArray(attrArr) || Array.isArray(attrArr) && !attrArr.length) {
        attrList = Object.keys(arrs[0])
        attrList.splice(attrList.indexOf(childs), 1)
      } else {
        attrList = attrArr
      }
      const list = []
      const getObj = (arr) => {
        arr.forEach(function(row) {
          const obj = {}
          attrList.forEach(item => {
            obj[item] = row[item]
          })
          list.push(obj)
          if (row[childs]) {
            getObj(row[childs])
          }
        })
        return list
      }
      return getObj(arrs)
    },