fix: add back last update time

frontend/src/Dashboard.tsx

@@ -85,7 +85,7 @@ function Dashboard(props: DashboardProps) {
   const { user, setUser } = useContext(LoginContext);
   const navigation = useNavigate();
 
-  const [time, setTime] = useState(Date.now());
+  const [time, setTime] = useState<Date>(new Date());
   const [refreshInterval, setRefreshInterval] = useState(0);
   const [refreshString, setRefreshString] = useState("manual");
 
@@ -93,20 +93,19 @@ function Dashboard(props: DashboardProps) {
   // update the time value every x ms, which triggers refresh (see below)
   useEffect(() => {
     if (refreshInterval === 0) {
-      console.log("refreshInterval is 0")
+      console.log("refreshInterval is 0");
       return;
     }
-    const interval = setInterval(() => setTime(Date.now()), refreshInterval);
+    const interval = setInterval(() => setTime(new Date()), refreshInterval);
     return () => {
-      console.log("clear refreshInterval")
+      console.log("clear refreshInterval");
       clearInterval(interval);
     };
   }, [refreshInterval]);
 
   // refresh every time the 'time' value changes
   useEffect(() => {
-    console.log("reload page at", time);
-    //setChildKey(prev => prev + 1);
+    console.log("reload page at", time.toISOString());
     props.refreshAction();
   }, [time]);
 
@@ -189,9 +188,17 @@ function Dashboard(props: DashboardProps) {
                   borderColor: "white",
                 }}
               />
-              <SimpleListMenu title={`Refresh: ${refreshString}`} options={refreshStrings} handleMenuItemClick={handleRefreshClick} />
+              <SimpleListMenu
+                title={`Refresh: ${refreshString}`}
+                options={refreshStrings}
+                handleMenuItemClick={handleRefreshClick}
+              />
             </Box>
-            <SimpleListMenu title={user?.username} options={["Change Password", "Logout"]} handleMenuItemClick={handleUserNameClick} />
+            <SimpleListMenu
+              title={user?.username}
+              options={["Change Password", "Logout"]}
+              handleMenuItemClick={handleUserNameClick}
+            />
           </Toolbar>
         </AppBar>
         <Drawer variant="permanent" open={open}>

frontend/src/pages/Charging/ChargingTable.tsx

@@ -10,6 +10,7 @@ import { Button, Grid } from "@mui/material";
 export default function ChargingTable() {
   const [expand, setExpand] = useState(true);
   const [refresh, setRefresh] = useState<boolean>(false);
+  const [updateTime, setUpdateTime] = useState<Date>(new Date());
 
   const [onlineChargingData, setOnlineChargingData] = useState<ChargingData[]>([]);
   const [offlineChargingData, setOfflineChargingData] = useState<ChargingData[]>([]);
@@ -44,10 +45,10 @@ export default function ChargingTable() {
   };
 
   const onRefresh = () => {
-    console.log("refreshing charging data");
     fetchChargingData("Online", setOnlineChargingData);
     fetchChargingData("Offline", setOfflineChargingData);
     fetchChargingRecord();
+    setUpdateTime(new Date());
   };
 
   useEffect(() => {
@@ -71,6 +72,21 @@ export default function ChargingTable() {
             {expand ? "Fold" : "Expand"}
           </Button>
         </Grid>
+        <Grid item>
+          <Button
+            color="secondary"
+            variant="contained"
+            onClick={() => onRefresh()}
+            sx={{ m: 2, backgroundColor: "blue", "&:hover": { backgroundColor: "blue" } }}
+          >
+            Refresh
+          </Button>
+        </Grid>
+        <Grid item>
+          <Button color="success" variant="contained" sx={{ m: 2 }} disabled>
+            Last update: {updateTime.toISOString().slice(0, 19).replace("T", " ")}
+          </Button>
+        </Grid>
       </Grid>
       <br />
       <ChargingList