This expression has a type of 'void' so its value can't be used - Flutter - flutter

Question

import 'package:demo_app/services/api.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
class AuthProvider extends ChangeNotifier{
bool isAuthenticated = false;
late String token;
late ApiService apiService;
AuthProvider() {
init();
}
Future<void> init() async {
token = await getToken();
if (token.isNotEmpty) {
isAuthenticated = true;
}
apiService = ApiService(token);
notifyListeners();
}
Future<void> register(String name, String email, String password, String passwordConfirm, String deviceName) async{
token = await apiService.register(name, email, password, passwordConfirm, deviceName);
isAuthenticated = true;
setToken();
notifyListeners();
}
Future<void> logIn(String email, String password, String deviceName) async{
token = await apiService.login(email, password, deviceName);
isAuthenticated = true;
setToken();
notifyListeners();
}
Future<void> logOut() async{
token = '';
isAuthenticated = false;
setToken();
notifyListeners();
}
Future<void> setToken() async{
final pref = await SharedPreferences.getInstance();
pref.setString('token', token);
}
Future<void> getToken() async{
final pref = await SharedPreferences.getInstance();
pref.getString('token') ?? '';
}
}
token = await getToken();
gives this error
This expression has a type of 'void' so its value can't be used.
Try checking to see if you're using the correct API; there might be a function or call that returns void you didn't expect. Also check type parameters and variables which might also be void.
Any clue on solving this issue?

Answer 1

Try the following code:
Future<void> init() async {
token = await getToken();
if (token.isNotEmpty) {
isAuthenticated = true;
}
apiService = ApiService(token);
notifyListeners();
}
Future<String> getToken() async {
final pref = await SharedPreferences.getInstance();
final token = pref.getString("token") ?? "";
return token;
}