From fe9bd73c3e498aa2157a6de580ee4b5bf8e17b7a Mon Sep 17 00:00:00 2001
From: Atridad Lahiji <me@atri.dad>
Date: Sun, 8 Oct 2023 13:21:30 -0600
Subject: [PATCH] Optimistic updates for votes

---
 app/(client)/room/[id]/VoteUI.tsx | 38 +++++++++++++++++++++++--------
 next.config.mjs                   |  3 +++
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/app/(client)/room/[id]/VoteUI.tsx b/app/(client)/room/[id]/VoteUI.tsx
index bfcd1f1..9408a25 100644
--- a/app/(client)/room/[id]/VoteUI.tsx
+++ b/app/(client)/room/[id]/VoteUI.tsx
@@ -4,6 +4,8 @@ import { EventTypes } from "@/_utils/types";
 import Image from "next/image";
 import { useEffect, useState } from "react";
 
+import { experimental_useOptimistic } from "react";
+
 import LoadingIndicator from "@/_components/LoadingIndicator";
 import type { PresenceItem, RoomResponse, VoteResponse } from "@/_utils/types";
 import { useUser } from "@clerk/nextjs";
@@ -36,9 +38,11 @@ const VoteUI = () => {
   const [copied, setCopied] = useState<boolean>(false);
 
   const [roomFromDb, setRoomFromDb] = useState<RoomResponse>();
-
   const [votesFromDb, setVotesFromDb] = useState<VoteResponse>(undefined);
 
+  const [optimisticVotes, setOptimisticVotes] =
+    experimental_useOptimistic(votesFromDb);
+
   const getRoomHandler = () => {
     fetch(`/api/internal/room/${roomId}`, {
       cache: "no-cache",
@@ -102,7 +106,8 @@ const VoteUI = () => {
   const getVoteForCurrentUser = () => {
     if (roomFromDb) {
       return (
-        votesFromDb && votesFromDb.find((vote) => vote.userId === user?.id)
+        optimisticVotes &&
+        optimisticVotes.find((vote) => vote.userId === user?.id)
       );
     } else {
       return null;
@@ -110,6 +115,19 @@ const VoteUI = () => {
   };
 
   const setVoteHandler = async (value: string) => {
+    const newVotes = optimisticVotes?.map((vote) => {
+      if (vote.userId === user?.id) {
+        return {
+          ...vote,
+          value,
+        };
+      } else {
+        return vote;
+      }
+    });
+
+    setOptimisticVotes(newVotes);
+
     if (roomFromDb) {
       await fetch(`/api/internal/room/${roomId}/vote`, {
         cache: "no-cache",
@@ -142,7 +160,7 @@ const VoteUI = () => {
   };
 
   const downloadLogs = () => {
-    if (roomFromDb && votesFromDb) {
+    if (roomFromDb && optimisticVotes) {
       const jsonObject = roomFromDb?.logs
         .map((item) => {
           return {
@@ -164,7 +182,7 @@ const VoteUI = () => {
           roomName: roomFromDb.roomName,
           storyName: storyNameText,
           scale: roomScale,
-          votes: votesFromDb.map((vote) => {
+          votes: optimisticVotes.map((vote) => {
             return {
               value: vote.value,
             };
@@ -301,10 +319,10 @@ const VoteUI = () => {
                           </p>
 
                           {roomFromDb &&
-                            votesFromDb &&
+                            optimisticVotes &&
                             voteString(
                               roomFromDb.visible,
-                              votesFromDb,
+                              optimisticVotes,
                               presenceItem.data
                             )}
                         </li>
@@ -395,7 +413,7 @@ const VoteUI = () => {
                             false,
                             true,
                             roomFromDb.storyName === storyNameText ||
-                              votesFromDb?.length === 0
+                              optimisticVotes?.length === 0
                               ? false
                               : true
                           )
@@ -408,7 +426,7 @@ const VoteUI = () => {
                         }
                       >
                         {roomFromDb.storyName === storyNameText ||
-                        votesFromDb?.length === 0 ? (
+                        optimisticVotes?.length === 0 ? (
                           <>
                             <IoReloadOutline className="text-xl mr-1" /> Reset
                           </>
@@ -420,9 +438,9 @@ const VoteUI = () => {
                       </button>
                     </div>
 
-                    {votesFromDb &&
+                    {optimisticVotes &&
                       (roomFromDb.logs.length > 0 ||
-                        votesFromDb.length > 0) && (
+                        optimisticVotes.length > 0) && (
                         <div>
                           <button
                             onClick={() => downloadLogs()}
diff --git a/next.config.mjs b/next.config.mjs
index f77e319..5720650 100644
--- a/next.config.mjs
+++ b/next.config.mjs
@@ -15,6 +15,9 @@ const config = {
       "img.clerk.com",
     ],
   },
+  experimental: {
+    serverActions: true,
+  },
 };
 
 export default config;