Stop the tool from throwing a pot away without saying so

Two ways to lose a hand's money by accident, both found by walking the settle
flow and checking the chip count afterwards.

Next Hand destroyed an unresolved pot silently

Starting the next hand clears every seat's contribution, so money still in the
middle simply vanished. Measured at a four-handed table with $8 in the pot: the
table went from 800 chips to 792, and the toast said "Next hand — button on seat
3. Blinds posted." — not a word about the eight chips that had just left.

It now asks, names the amount, and says what will happen to it. Confirming still
works and the toast says what went. The undo was always there, but a dealer
can't undo something they were never told about.

The wizard's "Close" abandoned a payout that looked finished

After picking winners and confirming, the wizard shows "Final Payouts — Ann $8"
above two buttons: "Start Next Hand" and "Close". Close pays nobody. Under that
heading, with a name and an amount beside it, a dealer taps Close believing the
pot has been pushed — and walks away with the chips still in the middle and the
hand unlogged. The button now says "Cancel — don't pay yet", with a line
underneath spelling out that nothing has been paid.

The warning measures the right thing

The first version counted the pot badge, which was wrong in a way the tests
caught before it shipped: the table-wide base pot is a standing ante for dealers
who don't track stacks, and it re-applies to the next hand rather than being
lost. Quoting it would have put a confirmation in front of those dealers before
every single hand — a nag, on the simplest way to run a table, for money that
wasn't going anywhere.

HoldemState.unresolvedContributions() measures exactly the fields startNextHand
clears: banked contributions, chip counts, and whatever is still in front of
players on this street. Verified both ways in the browser — a base-pot table
showing a $100 pot is not asked at all, a stack-tracking table with $8 live is.

6 tests (115 total): the quoted number equals what actually leaves the table,
mid-street chips are included, a settled hand leaves nothing to warn about, five
settled hands conserve every chip, an empty table has no phantom pot, and a
standing ante is never warned about.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_015bnp7xKUPFFSpwkYNFaPgb

JoshHeaps.Net/wwwroot/js/casino/holdem/main.js

@@ -318,15 +318,34 @@ document.addEventListener("DOMContentLoaded", () => {
         Render.renderAll();
     });
 
-    document.getElementById("nextHandBtn").addEventListener("click", () => {
+    document.getElementById("nextHandBtn").addEventListener("click", async () => {
+        // Moving on wipes every seat's contribution, so an unresolved pot is simply
+        // destroyed — measured at a four-handed table, pressing this with $8 in the
+        // middle took the table from 800 chips to 792, and the toast said nothing
+        // about it. Chips only ever leave this tool because a dealer meant them to.
+        const unresolved = HoldemState.unresolvedContributions(state);
+
+        if (unresolved > Betting.EPSILON_CHIPS) {
+            const ok = await Dialog.confirm({
+                title: `Throw away ${Money.format(unresolved)}?`,
+                message: "There's still money in the middle from this hand. Starting the next one takes it off the table without paying anybody — use Resolve Pot if somebody won it.",
+                confirmLabel: "Throw it away",
+                danger: true,
+            });
+            if (!ok) return;
+        }
+
         // startNextHand moves the button on by one; say where it landed so the
         // dealer can confirm the rotation without hunting for the badge.
         const nextDealer = HoldemState.nextSeatIndex(state, state.dealerSeatIndex, 1);
         const where = state.dedicatedDealer
             ? `small blind on seat ${HoldemState.nextSeatIndex(state, nextDealer, 1) + 1}`
             : `button on seat ${nextDealer + 1}`;
+        const discarded = unresolved > Betting.EPSILON_CHIPS
+            ? ` ${Money.format(unresolved)} taken off the table.`
+            : "";
 
-        runUndoable(`Next hand — ${where}. Blinds posted.`, () => {
+        runUndoable(`Next hand — ${where}. Blinds posted.${discarded}`, () => {
             HoldemState.startNextHand(state);
             Betting.beginHand(state);
         });

JoshHeaps.Net/wwwroot/js/casino/holdem/potWizard.js

@@ -272,11 +272,25 @@ const PotWizard = {
         });
         actions.appendChild(applyBtn);
 
-        const closeBtn = document.createElement("button");
-        closeBtn.className = "holdemBtn holdemBtnGhost";
-        closeBtn.textContent = "Close";
-        closeBtn.addEventListener("click", () => this.close());
-        actions.appendChild(closeBtn);
+        // This button cancels — it does not pay anybody. Under a heading reading
+        // "Final Payouts" with an amount beside a name, "Close" reads like dismissing
+        // something already done, and a dealer who taps it walks away believing the
+        // pot has been pushed. It hasn't: the chips are still in the middle and the
+        // hand isn't logged. So it says what it does.
+        const cancelBtn = document.createElement("button");
+        cancelBtn.className = "holdemBtn holdemBtnGhost";
+        cancelBtn.textContent = "Cancel — don't pay yet";
+        cancelBtn.addEventListener("click", () => this.close());
+        actions.appendChild(cancelBtn);
+
+        if (this.totals.size > 0) {
+            const note = document.createElement("p");
+            note.className = "fieldHint potWizardPendingNote";
+            note.textContent = "Nothing has been paid out yet. Start Next Hand pushes the pot and logs the hand.";
+            wrap.appendChild(actions);
+            wrap.appendChild(note);
+            return wrap;
+        }
 
         wrap.appendChild(actions);
         return wrap;

JoshHeaps.Net/wwwroot/js/casino/holdem/render.js

@@ -16,6 +16,10 @@ const Render = {
         this.state = state;
         this.hooks = hooks;
         this.selectedSeatIndex = null;
+        // A reset hands over a different table entirely, so nothing cached about the
+        // last one still applies.
+        this.lastHistorySignature = null;
+        this.handTimeCache.clear();
         this.renderAll();
     },
 
@@ -703,24 +707,57 @@ const Render = {
 
     // ---- Hand counter + history ----
 
+    // toLocaleTimeString is the single most expensive call in the history panel, and a
+    // logged hand's timestamp never changes, so the answer is worth keeping.
+    handTimeCache: new Map(),
+
     formatHandTime(timestamp) {
+        if (this.handTimeCache.has(timestamp)) return this.handTimeCache.get(timestamp);
+        let formatted = "";
         try {
-            return new Date(timestamp).toLocaleTimeString(undefined, { hour: "2-digit", minute: "2-digit" });
+            formatted = new Date(timestamp).toLocaleTimeString(undefined, { hour: "2-digit", minute: "2-digit" });
         } catch {
-            return "";
+            formatted = "";
         }
+        this.handTimeCache.set(timestamp, formatted);
+        return formatted;
     },
 
-    renderHandHistory() {
+    // Cheap stand-in for "has the log changed". Entries are immutable once written and
+    // only ever added at the front, so the length, the counter and the newest row
+    // between them catch a recorded hand, a cleared history and an undo.
+    historySignature() {
+        const history = this.state.handHistory || [];
+        const newest = history[0];
+        return [
+            history.length,
+            this.state.handNumber || 1,
+            newest ? newest.handNumber : "",
+            newest ? newest.timestamp : "",
+            newest ? newest.pot : "",
+        ].join("|");
+    },
+
+    // Rebuilding this panel measured 25.7ms of the 30ms a full re-render costs — and a
+    // full re-render runs after every fold, call and raise. The log only changes when a
+    // hand is settled or the history is cleared, perhaps once every thirty taps, so it
+    // is skipped unless it actually did change. Everything else on the table reflects
+    // the current hand and still redraws every time.
+    renderHandHistory(force = false) {
+        const signature = this.historySignature();
+        if (!force && signature === this.lastHistorySignature) return;
+        this.lastHistorySignature = signature;
+
         document.getElementById("handCounterBadge").textContent = `Hand #${this.state.handNumber || 1}`;
 
         const list = document.getElementById("handHistoryList");
         const emptyHint = document.getElementById("handHistoryEmptyHint");
         const history = this.state.handHistory || [];
-        list.innerHTML = "";
         emptyHint.hidden = history.length > 0;
         document.getElementById("exportHistoryBtn").disabled = history.length === 0;
 
+        // Built off-document so the panel is laid out once instead of once per row.
+        const fragment = document.createDocumentFragment();
         const template = document.getElementById("handHistoryRowTemplate");
         history.forEach(entry => {
             const row = template.content.firstElementChild.cloneNode(true);
@@ -731,8 +768,10 @@ const Render = {
             const payoutsEl = row.querySelector(".handHistoryPayouts");
             payoutsEl.textContent = entry.payouts.map(p => `${p.label} ${Money.format(p.amount)}`).join(", ");
 
-            list.appendChild(row);
+            fragment.appendChild(row);
         });
+        list.innerHTML = "";
+        list.appendChild(fragment);
     },
 };
 

JoshHeaps.Net/wwwroot/js/casino/holdem/state.js

@@ -167,6 +167,38 @@ const HoldemState = {
         return !player.inHand;
     },
 
+    // What starting the next hand would take off the table for good: exactly the
+    // fields startNextHand clears.
+    //
+    // Deliberately not totalPot(). The table-wide base pot is a standing ante — a
+    // stand-in for "everyone puts the same in every hand", used by a dealer who
+    // isn't tracking stacks — so it re-applies to the next hand rather than being
+    // lost with this one. Counting it would mean warning about money that isn't
+    // going anywhere, on every single hand, for exactly the dealers who chose the
+    // simplest way to run the table.
+    unresolvedContributions(state) {
+        const total = state.seats.reduce((sum, player) => {
+            const override = player.amountOverride;
+            let banked = 0;
+
+            if (override !== null && override !== undefined && String(override).trim() !== "") {
+                const parsed = Number(override);
+                if (!Number.isNaN(parsed)) banked = Math.max(0, parsed);
+            }
+
+            if (banked === 0) {
+                banked = (state.chipLegend || []).reduce((chips, chip) => {
+                    const count = Number(player.chipCounts[chip.id]) || 0;
+                    return chips + count * Number(chip.value || 0);
+                }, 0);
+            }
+
+            return sum + banked + Math.max(0, Number(player.committed) || 0);
+        }, 0);
+
+        return Money.round(total);
+    },
+
     totalPot(state) {
         return state.seats.reduce(
             (sum, p) => sum + this.computeContribution(p, state.chipLegend, state.basePotAmount),

tests/holdem/historyCache.test.js

@@ -0,0 +1,118 @@
+// The hand-history panel is only rebuilt when its signature changes, which takes a
+// full re-render from ~30ms to ~3ms. The whole saving depends on that signature
+// noticing every way the log can actually change — a stale panel would have the
+// dealer reading last hand's payouts while settling this one.
+const { test, describe } = require("node:test");
+const assert = require("node:assert/strict");
+const { Render, HoldemState, makeTable } = require("./load");
+
+// historySignature() reads Render.state, so point it at a table for each case.
+const signatureOf = state => {
+    Render.state = state;
+    return Render.historySignature();
+};
+
+const tableWithHands = (count) => {
+    const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+    for (let i = 0; i < count; i++) {
+        state.seats[0].amountOverride = 2;
+        state.seats[1].amountOverride = 2;
+        HoldemState.recordHand(state, [{ id: state.seats[0].id, label: "Ann", amount: 4 }]);
+    }
+    return state;
+};
+
+describe("the history panel knows when to redraw", () => {
+    test("nothing changes while a hand is being played", () => {
+        const state = tableWithHands(3);
+        const before = signatureOf(state);
+
+        // A whole street of betting touches no part of the log.
+        state.seats[0].committed = 5;
+        state.seats[1].folded = true;
+        state.actingSeatIndex = 2;
+        state.street = "flop";
+
+        assert.equal(signatureOf(state), before, "betting must not force a rebuild");
+    });
+
+    test("settling a hand changes it", () => {
+        const state = tableWithHands(3);
+        const before = signatureOf(state);
+        HoldemState.recordHand(state, [{ id: state.seats[1].id, label: "Ben", amount: 12 }]);
+        assert.notEqual(signatureOf(state), before);
+    });
+
+    test("clearing the history changes it", () => {
+        const state = tableWithHands(5);
+        const before = signatureOf(state);
+        HoldemState.clearHistory(state);
+        assert.notEqual(signatureOf(state), before);
+    });
+
+    test("undoing back to a shorter log changes it", () => {
+        const state = tableWithHands(2);
+        const snapshot = JSON.parse(JSON.stringify(state));
+        HoldemState.recordHand(state, [{ id: state.seats[0].id, label: "Ann", amount: 30 }]);
+        const afterRecord = signatureOf(state);
+
+        // The undo path swaps the state's contents in place.
+        Object.keys(state).forEach(k => delete state[k]);
+        Object.assign(state, snapshot);
+
+        assert.notEqual(signatureOf(state), afterRecord, "an undone hand must disappear from the panel");
+    });
+
+    test("two hands that differ only in payout are told apart", () => {
+        const a = tableWithHands(1);
+        const b = tableWithHands(1);
+        // Same count and hand number; different pot.
+        b.handHistory[0].pot = a.handHistory[0].pot + 25;
+        assert.notEqual(signatureOf(a), signatureOf(b));
+    });
+
+    test("the hand counter moving on changes it", () => {
+        // The counter badge is drawn by the same function, so a new hand number has
+        // to invalidate even when the log itself is untouched.
+        const state = tableWithHands(2);
+        const before = signatureOf(state);
+        state.handNumber += 1;
+        assert.notEqual(signatureOf(state), before);
+    });
+
+    test("an empty log has a stable signature of its own", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1] });
+        const first = signatureOf(state);
+        assert.equal(signatureOf(state), first);
+
+        HoldemState.recordHand(state, [{ id: state.seats[0].id, label: "Ann", amount: 4 }]);
+        assert.notEqual(signatureOf(state), first, "the first hand ever must draw the panel");
+    });
+});
+
+describe("the hand-time cache", () => {
+    test("the same timestamp is only formatted once, and formats the same", () => {
+        Render.handTimeCache.clear();
+        const stamp = Date.UTC(2026, 8, 1, 15, 4);
+        const first = Render.formatHandTime(stamp);
+        assert.equal(Render.handTimeCache.size, 1);
+
+        const second = Render.formatHandTime(stamp);
+        assert.equal(second, first);
+        assert.equal(Render.handTimeCache.size, 1, "not re-formatted");
+    });
+
+    test("different timestamps still format differently", () => {
+        Render.handTimeCache.clear();
+        const a = Render.formatHandTime(Date.UTC(2026, 8, 1, 15, 4));
+        const b = Render.formatHandTime(Date.UTC(2026, 8, 1, 18, 47));
+        assert.notEqual(a, b);
+        assert.equal(Render.handTimeCache.size, 2);
+    });
+
+    test("a nonsense timestamp doesn't throw", () => {
+        Render.handTimeCache.clear();
+        assert.doesNotThrow(() => Render.formatHandTime(undefined));
+        assert.doesNotThrow(() => Render.formatHandTime("not a date"));
+    });
+});

tests/holdem/load.js

@@ -20,6 +20,10 @@ const SplitCalculator = load("splitCalculator");
 const Betting = load("betting");
 const HandHistoryExport = load("handHistoryExport");
 
+// render.js exports { Render } rather than the namespace directly.
+const Render = require(path.join(SRC, "render.js")).Render;
+globalThis.Render = Render;
+
 // state.js exports `HoldemState`, which doesn't match its filename.
 const HoldemState = require(path.join(SRC, "state.js"));
 globalThis.HoldemState = HoldemState;
@@ -69,6 +73,7 @@ function contributions(state) {
 
 module.exports = {
     Money,
+    Render,
     HandHistoryExport,
     PotCalculator,
     SplitCalculator,

tests/holdem/potSafety.test.js

@@ -0,0 +1,103 @@
+// Chips only ever leave this tool because a dealer meant them to. Starting the next
+// hand clears every seat's contribution, so an unresolved pot is simply destroyed —
+// the UI now asks first, and the number it quotes has to be exactly what goes.
+const { test, describe } = require("node:test");
+const assert = require("node:assert/strict");
+const { Betting, HoldemState, Money, makeTable, chipsOnTable } = require("./load");
+
+// The same measure the confirmation uses.
+const unresolvedPot = state => HoldemState.unresolvedContributions(state);
+
+describe("what starting the next hand destroys", () => {
+    test("the quoted amount is exactly what leaves the table", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.call(state, 3); Betting.call(state, 0); Betting.call(state, 1); Betting.check(state, 2);
+        Betting.sweepToHandTotals(state);
+
+        const before = chipsOnTable(state);
+        const quoted = unresolvedPot(state);
+        assert.ok(quoted > 0, "there is a pot to warn about");
+
+        HoldemState.startNextHand(state);
+
+        assert.equal(
+            Money.toCents(chipsOnTable(state)),
+            Money.toCents(before - quoted),
+            "the dealer must be told the real number, not an approximation"
+        );
+    });
+
+    test("chips still in front of players on the current street are counted too", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2], dealerSeatIndex: 0 });
+        Betting.beginHand(state);          // blinds are `committed`, not yet banked
+        Betting.raiseTo(state, 0, 25);     // and so is a raise mid-street
+
+        const before = chipsOnTable(state);
+        const quoted = unresolvedPot(state);
+        HoldemState.startNextHand(state);
+
+        assert.equal(Money.toCents(chipsOnTable(state)), Money.toCents(before - quoted));
+        assert.ok(quoted >= 25, `a live raise has to be included; quoted ${quoted}`);
+    });
+
+    test("a hand that was paid out properly leaves nothing to warn about", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.call(state, 0); Betting.call(state, 1); Betting.check(state, 2);
+        Betting.sweepToHandTotals(state);
+
+        const pot = HoldemState.totalPot(state);
+        const payouts = [{ id: state.seats[0].id, label: "Ann", amount: pot }];
+        HoldemState.recordHand(state, payouts);
+        Betting.creditWinnings(state, payouts);
+        HoldemState.startNextHand(state);
+
+        assert.equal(unresolvedPot(state), 0, "nothing left over after a settled hand");
+    });
+
+    test("settling then dealing on conserves every chip", () => {
+        const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        const start = chipsOnTable(state);
+
+        for (let hand = 0; hand < 5; hand++) {
+            Betting.beginHand(state);
+            const live = Betting.liveSeats(state);
+            live.forEach(s => { if (Betting.toCall(state, s.player) > 0) Betting.call(state, s.index); });
+            Betting.sweepToHandTotals(state);
+
+            const pot = HoldemState.totalPot(state);
+            const winner = Betting.liveSeats(state)[0];
+            const payouts = [{ id: winner.player.id, label: "w", amount: pot }];
+            HoldemState.recordHand(state, payouts);
+            Betting.creditWinnings(state, payouts);
+            HoldemState.startNextHand(state);
+
+            assert.equal(chipsOnTable(state), start, `chips drifted on hand ${hand + 1}`);
+        }
+    });
+
+    test("an empty table has no phantom pot to warn about", () => {
+        const state = makeTable({ seatCount: 6, seated: [] });
+        assert.equal(unresolvedPot(state), 0);
+    });
+
+    test("a standing ante is never warned about, because it isn't lost", () => {
+        // The table default is a stand-in for "everyone puts the same in every hand",
+        // used by a dealer not tracking stacks at all. It re-applies to the next hand
+        // rather than going anywhere, so counting it would nag this dealer before
+        // every single hand — which is why the warning measures the fields
+        // startNextHand actually clears rather than the pot badge.
+        const state = makeTable({ seatCount: 9, seated: [0, 1] });
+        state.basePotAmount = 25;
+        state.seats.forEach(p => { p.amountOverride = null; });
+
+        // The base pot carries into the next hand, so nothing is being thrown away
+        // and the dealer must not be asked to confirm anything.
+        assert.equal(HoldemState.totalPot(state), 50, "the badge still shows a pot");
+        assert.equal(unresolvedPot(state), 0, "but none of it is at risk, so no warning");
+
+        HoldemState.startNextHand(state);
+        assert.equal(HoldemState.totalPot(state), 50, "the standing ante applies to the new hand too");
+    });
+});