DataScience-GT · aamoghS · Sep 24, 2026 · Sep 24, 2026 · Sep 24, 2026
@@ -29,7 +29,7 @@
     "@typescript-eslint/parser": "^8.70.1",
     "@typescript-eslint/utils": "^8.70.1",
     "eslint": "^10.11.0",
-    "eslint-config-prettier": "^10.1.5",
+    "eslint-config-prettier": "^10.1.8",
     "typescript": "^7.0.2"
   }
 }
@@ -1,5 +1,5 @@
 "use client";
-import React, { useState, useEffect } from "react";
+import React, { useState, useEffect, useSyncExternalStore } from "react";
 import HomeSections from "@/components/HomeSections";
 import PixelGarden, { PixelGround } from "@/components/pixel/PixelGarden";
 import PixelSprite from "@/components/pixel/PixelSprite";
@@ -57,6 +57,8 @@ const FloralBackground = () => (
 );
 
 // ─── Countdown ────────────────────────────────────────────────────────────
+const subscribeNoop = () => () => {};
+
 const Countdown: React.FC<{ targetDate: Date }> = ({ targetDate }) => {
   const getTimeLeft = React.useCallback(() => {
     const distance = targetDate.getTime() - Date.now();
@@ -69,12 +71,12 @@ const Countdown: React.FC<{ targetDate: Date }> = ({ targetDate }) => {
     };
   }, [targetDate]);
 
-  const [timeLeft, setTimeLeft] = useState<{ days: number; hours: number; minutes: number; seconds: number } | null>(null);
-  const [mounted, setMounted] = useState(false);
+  const [timeLeft, setTimeLeft] = useState(getTimeLeft);
+  // False for the static HTML and hydration, true after: the build-time
+  // countdown would be stale by the time anyone loads the page.
+  const mounted = useSyncExternalStore(subscribeNoop, () => true, () => false);
 
   useEffect(() => {
-    setMounted(true);
-    setTimeLeft(getTimeLeft());
     const id = setInterval(() => setTimeLeft(getTimeLeft()), 1000);
     return () => clearInterval(id);
   }, [getTimeLeft]);

@@ -32,12 +32,6 @@ export default function LazySection({
     const el = ref.current;
     if (!el) return;
 
-    // If IntersectionObserver isn't available, render immediately
-    if (typeof IntersectionObserver === "undefined") {
-      setIsVisible(true);
-      return;
-    }
-
     const observer = new IntersectionObserver(
       ([entry]) => {
         if (entry.isIntersecting) {

@@ -5,6 +5,7 @@ import { Zap } from "lucide-react";
 import { useSession } from "next-auth/react";
 import { trpc } from "@/lib/trpc";
 import { usePortalContext } from "@/lib/use-portal-context";
+import { useIsClient } from "@/lib/use-is-client";
 import { useRouter } from "next/navigation";
 import { LiquidGlass } from "@/components/portal/LiquidGlass";
 import { JudgingTools } from "@/components/admin/judging/JudgingTools";
@@ -18,7 +19,7 @@ import { judgingPrepIsCurrent } from "@/lib/judging-prep";
 export default function AdminResultsPage() {
   const { data: session, status } = useSession();
   const router = useRouter();
-  const [mounted, setMounted] = useState(false);
+  const mounted = useIsClient();
   const [selectedHackathon, setSelectedHackathon] = useState<string | null>(
     null,
   );
@@ -76,7 +77,6 @@ export default function AdminResultsPage() {
     null,
   );
   const selectedHackathonRef = useRef(selectedHackathon);
-  selectedHackathonRef.current = selectedHackathon;
   const prepGen = useRef(0);
 
   const promoteSubmissions = trpc.judge.promoteSubmissions.useMutation();
@@ -172,29 +172,41 @@ export default function AdminResultsPage() {
     }
   };
 
-  useEffect(() => {
-    setMounted(true);
-  }, []);
-
   useEffect(() => {
     if (status === "unauthenticated") {
       router.push("/login");
     }
   }, [status, router]);
 
   // Auto-select first hackathon
-  useEffect(() => {
-    if (hackathons?.[0] && !selectedHackathon) {
-      setSelectedHackathon(hackathons[0].id);
-    }
-  }, [hackathons, selectedHackathon]);
-
-  useEffect(() => {
-    prepGen.current += 1;
+  if (hackathons?.[0] && !selectedHackathon) {
+    setSelectedHackathon(hackathons[0].id);
+  }
+
+  // A new selection drops the previous edition's prep result and conflict.
+  const [prepShownFor, setPrepShownFor] = useState(selectedHackathon);
+  if (prepShownFor !== selectedHackathon) {
+    setPrepShownFor(selectedHackathon);
     setAssignConflictId(null);
     setPrepState({ busy: false, message: null, error: null });
+  }
+
+  // Covers the auto-select above, which runs before any prep can start.
+  useEffect(() => {
+    selectedHackathonRef.current = selectedHackathon;
   }, [selectedHackathon]);
 
+  // The ref and generation move here, in the click, before B renders: a run
+  // still in flight for A fails stillThisRun from this moment, so its result
+  // cannot land on B's panel. Re-selecting the current edition is a no-op, so
+  // it cannot orphan that edition's own run with busy stuck on.
+  const selectHackathon = (id: string) => {
+    if (id === selectedHackathonRef.current) return;
+    selectedHackathonRef.current = id;
+    prepGen.current += 1;
+    setSelectedHackathon(id);
+  };
+
   const categories = useMemo(() => {
     if (!rankings?.rankings) return ["ALL"];
     const cats = new Set(
@@ -451,7 +463,7 @@ export default function AdminResultsPage() {
         <JudgingTools
           hackathons={hackathons || []}
           selectedHackathon={selectedHackathon}
-          setSelectedHackathon={setSelectedHackathon}
+          setSelectedHackathon={selectHackathon}
           viewMode={viewMode}
           setViewMode={setViewMode}
           categories={categories}

@@ -51,11 +51,13 @@ export default function AdminResumesPage() {
 
   // A selection or page carried across a filter change would put people in a
   // book the list said it would not.
-  useEffect(() => {
+  const [filterShown, setFilterShown] = useState({ scope, debounced });
+  if (filterShown.scope !== scope || filterShown.debounced !== debounced) {
+    setFilterShown({ scope, debounced });
     setSelected(new Set());
     setPreview(null);
     setOffset(0);
-  }, [scope, debounced]);
+  }
 
   const allChecked = rows.length > 0 && rows.every((r) => selected.has(r.userId));
 

@@ -118,11 +118,13 @@ export default function ClubPage() {
     }
   }, [status, memberStatus, router]);
 
-  useEffect(() => {
-    if (!showScanner) {
-      setScannedCodes(new Set());
-    }
-  }, [showScanner]);
+  // Closing the scanner forgets what it saw, so reopening can scan the same
+  // code again.
+  const [scannerWasOpen, setScannerWasOpen] = useState(showScanner);
+  if (showScanner !== scannerWasOpen) {
+    setScannerWasOpen(showScanner);
+    if (!showScanner) setScannedCodes(new Set());
+  }
 
   const handleScan = async (detectedCodes: { rawValue: string }[]) => {
     if (isProcessing || !detectedCodes || detectedCodes.length === 0) return;

@@ -128,17 +128,16 @@ export default function JudgeHackathonPage() {
   // Seeds the first project only. Once a mutation has taken over, `current` or
   // `done` is set and a late-arriving response must not replace what the judge
   // is looking at.
-  useEffect(() => {
-    if (!nextTable.data || current || done) return;
+  if (nextTable.data && !current && !done) {
     if (nextTable.data.done) {
       setDone(true);
-      return;
+    } else {
+      setCurrent({
+        project: (nextTable.data.project as Project) ?? null,
+        queueId: nextTable.data.queueId ?? null,
+      });
     }
-    setCurrent({
-      project: (nextTable.data.project as Project) ?? null,
-      queueId: nextTable.data.queueId ?? null,
-    });
-  }, [nextTable.data, current, done]);
+  }
 
   const advance = (
     project: Project | null,

@@ -1,9 +1,10 @@
 "use client";
 
-import { useEffect, useState } from "react";
+import { useEffect } from "react";
 import { useSession } from "next-auth/react";
 import { useRouter } from "next/navigation";
 import { trpc } from "@/lib/trpc";
+import { useIsClient } from "@/lib/use-is-client";
 import { LiquidGlass } from "@/components/portal/LiquidGlass";
 import { LoadingScreen } from "@/components/portal/LoadingScreen";
 import Link from "next/link";
@@ -24,7 +25,7 @@ type HackathonData = {
 export default function JudgePage() {
   const { data: session, status } = useSession();
   const router = useRouter();
-  const [mounted, setMounted] = useState(false);
+  const mounted = useIsClient();
 
   const { data: judgeStatus, isLoading: checkingJudge } =
     trpc.judge.isJudge.useQuery(undefined, { enabled: !!session });
@@ -41,8 +42,6 @@ export default function JudgePage() {
     enabled: !!session,
   });
 
-  useEffect(() => setMounted(true), []);
-
   // The approval email points here. Rendering nothing for a signed-out visitor
   // turned an expired session into a broken link.
   useEffect(() => {

@@ -5,6 +5,7 @@ import { useSession, signIn, getProviders } from "next-auth/react";
 import { useRouter, useSearchParams } from "next/navigation";
 import { usePortalContext } from "@/lib/use-portal-context";
 import { safeCallback } from "@/lib/safe-callback";
+import { useIsClient } from "@/lib/use-is-client";
 
 // DSGT Query - Premium Landing Page
 // Ultra-modern, standout UI/UX
@@ -14,7 +15,7 @@ export default function Home() {
   const router = useRouter();
   const searchParams = useSearchParams();
   const callbackUrl = safeCallback(searchParams.get("callbackUrl"));
-  const [mounted, setMounted] = useState(false);
+  const mounted = useIsClient();
   const [showEmailInput, setShowEmailInput] = useState(false);
   const [email, setEmail] = useState("");
   const [emailSending, setEmailSending] = useState(false);
@@ -37,7 +38,6 @@ export default function Home() {
   );
 
   useEffect(() => {
-    setMounted(true);
     getProviders()
       .then((p) => setProviders(p ?? {}))
       // A failed lookup must not hide every sign-in button. Falling back to

@@ -25,14 +25,15 @@ import { ResumeSection } from "@/components/portal/ResumeSection";
 import Image from "next/image";
 import { trpc } from "@/lib/trpc";
 import { trpcErrorMessage } from "@/lib/trpc-error";
+import { useIsClient } from "@/lib/use-is-client";
 import { LiquidGlass } from "@/components/portal/LiquidGlass";
 import { LoadingScreen } from "@/components/portal/LoadingScreen";
 
 export default function SettingsPage() {
   const { data: session, status } = useSession();
   const router = useRouter();
   const { theme, setTheme } = useTheme();
-  const [mounted, setMounted] = useState(false);
+  const mounted = useIsClient();
   const [activeTab, setActiveTab] = useState<
     "profile" | "membership" | "appearance" | "account"
   >("profile");
@@ -123,23 +124,23 @@ export default function SettingsPage() {
     gtEmail: "",
   });
 
-  useEffect(() => { setMounted(true); }, []);
-
   useEffect(() => {
     if (status === "unauthenticated") router.push("/login");
   }, [status, router]);
 
-  useEffect(() => {
-    if (userData) {
-      setForm({
-        name: userData.name || "",
-        bio: userData.bio || "",
-        website: userData.website || "",
-        location: userData.location || "",
-        gtEmail: userData.gtEmail || "",
-      });
-    }
-  }, [userData]);
+  // Refill the form whenever new user data arrives. Done during render rather
+  // than in an effect, so the stale form never paints.
+  const [filledFrom, setFilledFrom] = useState<typeof userData>(undefined);
+  if (userData && userData !== filledFrom) {
+    setFilledFrom(userData);
+    setForm({
+      name: userData.name || "",
+      bio: userData.bio || "",
+      website: userData.website || "",
+      location: userData.location || "",
+      gtEmail: userData.gtEmail || "",
+    });
+  }
 
   const handleSave = async () => {
     setIsSaving(true);

@@ -3,7 +3,7 @@
 import { useSession } from "next-auth/react";
 import { trpc } from "@/lib/trpc";
 import { useRouter, useSearchParams } from "next/navigation";
-import { Suspense, useEffect, useState } from "react";
+import { Suspense, useState } from "react";
 import { LiquidGlass } from "@/components/portal/LiquidGlass";
 import { LoadingScreen } from "@/components/portal/LoadingScreen";
 import Link from "next/link";
@@ -191,24 +191,22 @@ function SubmitPortalContent() {
     onError: (err) => setError(err.message),
   });
 
-  useEffect(() => {
-    if (!selectedHackathonId && myRegs && myRegs.length > 0) {
-      const firstReg = myRegs[0];
-      if (firstReg) {
-        setSelectedHackathonId(firstReg.hackathonId);
-      }
+  if (!selectedHackathonId && myRegs && myRegs.length > 0) {
+    const firstReg = myRegs[0];
+    if (firstReg) {
+      setSelectedHackathonId(firstReg.hackathonId);
     }
-  }, [myRegs, selectedHackathonId]);
+  }
 
   // Fill the form from the existing submission, once per selected event.
   // Clearing when there is none matters as much as filling: the form used to
   // keep the previous event's answers after switching, so a submit could file
   // one hackathon's project against another.
-  useEffect(() => {
-    if (!selectedHackathonId) return;
-    if (mySubmission.isPending) return;
-    if (prefilledFor === selectedHackathonId) return;
-
+  if (
+    selectedHackathonId &&
+    !mySubmission.isPending &&
+    prefilledFor !== selectedHackathonId
+  ) {
     const p = mySubmission.data;
     setProjectName(p?.name ?? "");
     setProjectDesc(p?.description ?? "");
@@ -219,12 +217,7 @@ function SubmitPortalContent() {
     setChallenges(p?.challenges ?? []);
     setIsCreateX(p?.isCreateX ?? false);
     setPrefilledFor(selectedHackathonId);
-  }, [
-    selectedHackathonId,
-    mySubmission.isPending,
-    mySubmission.data,
-    prefilledFor,
-  ]);
+  }
 
   if (status === "loading" || loadingRegs) {
     return <LoadingScreen message="Initializing Workspace…" />;

@@ -98,8 +98,9 @@ function VerifyContent() {
         // /dashboard by the route, so the `||` below can never fall through to
         // anything else — reading the query param first is what actually
         // returns somebody to the page that sent them here.
-        window.location.href =
-          callbackUrl || data.redirectUrl || "/dashboard";
+        window.location.assign(
+          callbackUrl || data.redirectUrl || "/dashboard",
+        );
       } else {
         setError(data.error || "Invalid code. Please try again.");
         setVerifying(false);