React, ts 函数调用基础问题

Question

如下,生命周期函数queryDataById时,在参数里又调用了handleUpdate
this.handleUpdate 与 update 有关系吗?
update() 执行了什么内容 ?

  componentDidMount() {
    queryDataById("ROOT", this.handleUpdate);
  }

  handleUpdate = () => {
    this.setState(v => {
      return {
        count: v.count + 1
      };
    });
  };

const queryDataById = async (id: string, update: () => void) => {
  let res = await needAPI(id);
  let node = treeNodeMap[id];
  if ("children" in node) {
    node.children = res;
    res.forEach(item => {
      treeNodeMap[item.id] = item;
    });
    update();
  }
};

Answer 1

不就是形参和实参么……