树结构，当节点的children为空时，删除children

// children为[],则删除children键
  function deleteChildren(arr) {
      let childs = arr
      for (let i = childs.length; i--; i > 0) {
        if (childs[i].children) {
          if (childs[i].children.length) {
            this.deleteChildren(childs[i].children)
          } else {
            delete childs[i].children
          }
        }
      }
      return arr
    }

使用

let arrNew = deleteChildren(arr2)
console.log(arrNew)