useReducer about react HOT 1 CLOSED

/*
 * @Author: [email protected]
 * @Date: 2021-08-25 15:12:55
 * @LastEditTime: 2021-08-25 16:15:56
 * @LastEditors: [email protected]
 * @Description: 
 * @FilePath: \test\src\App.js
 */
import { useState, useReducer } from "react"
import './App.css';
function reducer(state, action) {
  switch (action.type) {
    case 'change':
      return {
        ...state,
        name: action.params.name
      }
    default:
      throw new Error();
  }
}
function App() {
  const initialState = { id: "", name: "duxin", age: "18" };
  const [state, dispatch] = useReducer(reducer, initialState);
  const [age, setAge] = useState({age:19,num:"908"});
  const changeInput = ({ target: { value } }) => {
    dispatch({ type: "change", params: { name: value } })
  }
  const changeAge = () => {
    let _age = age;
    _age.age++;
    setAge({..._age});
  }
  return (
    <div className="App">
      <input onChange={changeInput} />
      <div>{state.name}</div>
      <hr />
      <button onClick={changeAge}>更新</button>
      <p>{age.age}</p>
    </div>
  );
}

export default App;