update comments in useSharedState

custom/shared/hooks/useSharedState.js

@@ -15,15 +15,17 @@ export const useSharedState = ({ initialValues = {}, broadcast = true }) => {
 
   // handling the app-message event, to check if the state is being shared.
   const handleAppMessage = useCallback(
-    event => {
+    (event) => {
       // two types of events -
       // 1. Request shared state (request-shared-state)
       // 2. Set shared state (set-shared-state)
       switch (event.data?.message?.type) {
         // if we receive a request-shared-state message type, we check if the user has any previous state,
-        // if yes, we will send the shared-state to everyone in the call.
         case 'request-shared-state':
+          // do not respond if there is no available state
           if (!stateRef.current.setAt) return;
+
+          // if there is, we will send the shared-state to everyone in the call
           callObject.sendAppMessage(
             {
               message: {
@@ -31,23 +33,27 @@ export const useSharedState = ({ initialValues = {}, broadcast = true }) => {
                 value: stateRef.current,
               },
             },
-            '*',
+            '*'
           );
           break;
         // if we receive a set-shared-state message type then, we check the state timestamp with the local one and
         // we set the latest shared-state values into the local state.
         case 'set-shared-state':
           clearInterval(requestIntervalRef.current);
+          // do not respond if the current state is more up-to-date than the state being shared
           if (
             stateRef.current.setAt &&
-            new Date(stateRef.current.setAt) > new Date(event.data.message.value.setAt)
-          )
+            new Date(stateRef.current.setAt) >
+              new Date(event.data.message.value.setAt)
+          ) {
             return;
+          }
+          // update the state
           setState(event.data.message.value);
           break;
       }
     },
-    [stateRef, callObject],
+    [stateRef, callObject]
   );
 
   // whenever local user joins, we randomly pick a participant from the call and request him for the state.
@@ -60,32 +66,45 @@ export const useSharedState = ({ initialValues = {}, broadcast = true }) => {
       const localParticipant = callObjectParticipants.local;
 
       if (participants.length > 1) {
-        const remoteParticipants = participants.filter((p) =>
-          !p.local && new Date(p.joined_at) < new Date(localParticipant.joined_at)
+        const remoteParticipants = participants.filter(
+          (p) =>
+            !p.local &&
+            new Date(p.joined_at) < new Date(localParticipant.joined_at)
         );
-        const randomPeer = remoteParticipants[Math.floor(Math.random() * remoteParticipants.length)];
+
+        const randomPeer =
+          remoteParticipants[
+            Math.floor(Math.random() * remoteParticipants.length)
+          ];
+
+        // send the request for the shared state
         callObject.sendAppMessage(
           {
             message: {
               type: 'request-shared-state',
             },
           },
-          randomPeer.user_id,
+          randomPeer.user_id
         );
-      } else clearInterval(requestIntervalRef.current);
+      } else {
+        // if there is only one participant, don't try to request shared state again
+        clearInterval(requestIntervalRef.current);
+      }
     }, randomDelay);
 
     return () => clearInterval(requestIntervalRef.current);
   }, [callObject]);
 
+  // Add event listeners to the Daily call object if it exists
   useEffect(() => {
     if (!callObject) return;
     callObject.on('app-message', handleAppMessage);
     callObject.on('joined-meeting', handleJoinedMeeting);
+
     return () => {
       callObject.off('app-message', handleAppMessage);
       callObject.off('joined-meeting', handleJoinedMeeting);
-    }
+    };
   }, [callObject, handleAppMessage, handleJoinedMeeting]);
 
   useEffect(() => {
@@ -96,10 +115,16 @@ export const useSharedState = ({ initialValues = {}, broadcast = true }) => {
   // 1. shares the state with everyone in the call.
   // 2. set the state for the local user.
   const setSharedState = useCallback(
-    values => {
+    (values) => {
       setState((state) => {
-        const currentValues = typeof values === 'function' ? values(state.sharedState) : values;
-        const stateObj = { ...state, sharedState: currentValues, setAt: new Date() };
+        const currentValues =
+          typeof values === 'function' ? values(state.sharedState) : values;
+
+        const stateObj = {
+          ...state,
+          sharedState: currentValues,
+          setAt: new Date(),
+        };
         // if broadcast is true, we send the state to everyone in the call whenever the state changes.
         if (broadcast) {
           callObject.sendAppMessage(
@@ -109,15 +134,15 @@ export const useSharedState = ({ initialValues = {}, broadcast = true }) => {
                 value: stateObj,
               },
             },
-            '*',
+            '*'
           );
         }
         return stateObj;
       });
-
-    }, [broadcast, callObject],
+    },
+    [broadcast, callObject]
   );
 
   // returns back the sharedState and the setSharedState function
   return { sharedState: state.sharedState, setSharedState };
-};
+};