反应状态不使用钩子更新

时间:2021-04-14 07:59:15

标签: javascript reactjs use-state

我在组件中有以下代码: 我无法获得更新的状态。

当我调用 createUserList 时,我可以在 UserList 组件中看到用户,但在 UserComponet 中,当我登录用户时,我看不到那里的用户。

我使用的代码:

function UserComponent() {
    const [users, setUsers] = useState<any>([])


  const register = () => {
    userAgent.delegate = {
      onMessage(message: Message) {
        let usernameList = message.event.entry
        if (message.event['@_category'] === 'activate') {
          createUserList(usernameList); 
        } else if (message.event['@_category'] === 'de-activate') {
          
          // empty user list but I can see users in react dev tools
          console.log(users)
          const username = message.event.entry
          removeUser(username)
        }
      }
    }
  }

  const createUserList = (usernameList: any) => {
    let userList: any = []
    usernameList.forEach((user: any) => {
      userList.push({'uri': user['@_uri'], 'name': user['@_uri'].substr(10, 8)})
    })

    // here I can see updated userList
    console.log(userList)
    setUsers(userList)
    setTimeout(() => {

      // users is empty here
      console.log(users)
    }, 5000)
  }

  return (
    <UserList users={users}/>
  )

}

function UserList({users}) {
    return (
        <div>
            {users.map((user) => <h2>user</h2>)}
        </div>
    )
}

0 个答案:

没有答案