无法在 useEffect 挂钩内设置 state

Question

I can see response object containing array of users, but it seems setState doesn't work inside useEffect() hook.

This is request code.

     const [users,setUsers] = useState([]);
     const getUsers=async()=>{
         await axios.get(API_URL,{
             headers:{
                 'Content-Type': 'application/json',
                     'Accept': 'application/json',
                     'Access-Control-Allow-Origin': '*'
             }
         })
         .then((res)=>{
            const data = res.data.users;
             console.log(data);
            setUsers([...users,data]);
            console.log(users);
            
         })
         .catch((err)=>{
             console.log(err);
         })
     }
     useEffect(()=>{
         
         getUsers();
     },[])

Answer 1

setUsers() is the asynchronous method, and you can't get the updated value of users immediately after setusers() .

setUsers([...users,data]);
console.log(users); // This will console old value of users

You should use useEffect with adding a users dependency to check the updated value of users .

useEffect(() => {
  console.log(users);
}, [users]);