React projects cannot save store? using redux, data - Codes Helper

react projects cannot save store? using redux, data

index.js

ReactDOM.render(
  <Provider store={store}>
    <Router />
  </Provider>, document.getElementById("root"))
registerServiceWorker()

actions


export const SET_USER = "SET_USER"
export const LOGOUT = "LOGOUT"

export function setuser(login) {
  return {type: SET_USER, login}
}
export function logout(user) {
  return {type: LOGOUT, user}
}

reducers

import { combineReducers } from "redux"
import { SET_USER, LOGOUT } from "../actions"

function setuser(state = "1118", action) {
  switch(action.type) {
    case SET_USER:
      return action.login
    case LOGOUT:
      return ""
    default:
     return state
  }
}
const yg = combineReducers({
  setuser
})
export default yg

use:

class page1 extends Component {
  componentDidMount() {
    this.props.dispatch(setuser("555"))
    console.log(this.props.login)
    console.log("111")
  }
  render() {
    return (
        <Content style={{ padding: "0 10px" }}>
          <Breadcrumb style={{ margin: "8px 0", position: "relative" }} separator=">">
            <Breadcrumb.Item><Icon type="environment-o" /></Breadcrumb.Item>
            <Breadcrumb.Item>List</Breadcrumb.Item>
            <Breadcrumb.Item>App</Breadcrumb.Item>
            <div style={{ position: "absolute", right: "0px", top: "-6px"}}>
              <div style={{ float: "left", marginRight: "10px" }}>
                <Avatar style={{ backgroundColor: "-sharp87d068", marginRight: "5px", marginTop: "1px" }} icon="user" />
                <Popover placement="bottom" title="" content={content} trigger="click">
                  <Button type="dashed">user</Button>
                </Popover>
              </div>
              <div style={{ float: "left", marginRight: "10px" }}>
                <Avatar style={{ backgroundColor: "-sharp13c2c2", marginRight: "5px" }} icon="hdd" />
                <Button type="dashed">6+666</Button>
              </div>
              <div style={{ float: "left" }}>
                <Avatar style={{ backgroundColor: "-sharp2f54eb", marginRight: "5px" }} icon="calendar" />
                <Button type="dashed">year</Button>
              </div>
            </div>
          </Breadcrumb>
          <Layout style={{ padding: "24px 0", background: "-sharpfff" }}>
            <Sider width={200} style={{ background: "-sharpfff" }}>
              <Antdleftbar />
            </Sider>
            <Content style={{ padding: "0 24px", minHeight: 280, marginLeft: "50px" }}>
              <Antdtable />
            </Content>
          </Layout>
        </Content>
    )
  }
}
function select(state) {
  return {
    login: state.login
  }
}
export default connect(select)(page1)

the output result is
undefined
111

the previous project was effective in this way, but it didn"t work for half a year, but now it"s become like this. I don"t understand why
some places say that in order to solve the problem of React 0.13,
must be wrapped in a function with child
, but change to
{() = > < Router / >}
will show

React.Children.only expected to receive a single React element child.
 23 stack frames were collapsed.
./src/index.js
D:/software/workspace/bj_zbzq_ext/src/index.js:11
   8 | import yg from "./reducers"
   9 | let store = createStore(yg)
  10 | 
> 11 | ReactDOM.render(
  12 |   <Provider store={store}>
  13 |     { () => <Router /> }
  14 |   </Provider>, document.getElementById("root"))

I don"t understand why. I hope Daniel can help me to see what the problem is