Stop rebuilding the hand log after every fold, call and raise

Profiled a long night at a full table — 24 seats, 200 logged hands — because that's the state the tool is slowest in and the one a dealer reaches at 2am. A full re-render cost 30ms, and it runs after every single action. Broken down, 25.7ms of that was renderHandHistory: tearing down and rebuilding 200 rows of a panel that hadn't changed and that nobody is looking at mid-hand. Everything else on the table put together came to about 4ms. The log only changes when a hand is settled or the history is cleared — maybe once every thirty taps. It now carries a cheap signature (length, hand counter, and the newest row) and is skipped when that hasn't moved. Entries are immutable once written and only ever added at the front, so the signature catches a recorded hand, a cleared history, and an undo that puts a hand back. renderAll, every action 30.07ms -> 4.18ms renderHandHistory, skipped 25.74ms -> 0ms renderHandHistory, rebuild 25.74ms -> 9.05ms The rebuild got faster too, for the times it does run — once per hand, where 25ms of jank lands exactly on the "next hand" tap. toLocaleTimeString was the single most expensive call in the loop and a logged hand's timestamp never changes, so the formatted string is kept; and the rows are built into a fragment so the panel lays out once instead of two hundred times. A cache like this is only worth having if it can't go stale — a dealer reading last hand's payouts while settling this one is worse than a slow panel. 10 tests cover the invalidation directly: unchanged through a street of betting, changed by settling, by clearing, by an undo back to a shorter log, by two hands that differ only in the pot, and by the counter moving on. Validated with Playwright against the real page: the rendered rows match the stored history through settling a hand in the wizard, undoing it, clearing the log and recording again. Touch and layout guarantees from the earlier rounds still hold — 0 of 87 controls on touch-action auto, 0 tap-highlighted, every stack still inside its own puck. 109 tests passing. Co-Authored-By: Claude Opus 5 <[email protected]> Claude-Session: https://claude.ai/code/session_015bnp7xKUPFFSpwkYNFaPgb
Make the overlays usable from a keyboard
2026-09-01 04:24:36 -06:00 · 2026-09-01 04:12:55 -06:00 · 2026-09-01 03:54:03 -06:00
13 changed files with 721 additions and 38 deletions
@@ -138,7 +138,7 @@
            <details class="sidebarPanel">
                <summary>Table Notes</summary>
                <div class="panelBody">
-                    <textarea id="tableNotes" rows="4" placeholder="Anything else worth tracking — side bets, IOUs, running totals..."></textarea>
+                    <textarea id="tableNotes" rows="4" aria-label="Table notes" placeholder="Anything else worth tracking — side bets, IOUs, running totals..."></textarea>
                </div>
            </details>
        </aside>
@@ -198,8 +198,8 @@

 <template id="chipLegendRowTemplate">
    <div class="chipLegendRow">
-        <input type="color" class="chipColorInput" />
-        <input type="number" class="chipValueInput" min="0" step="0.01" placeholder="value" />
+        <input type="color" class="chipColorInput" aria-label="Chip colour" />
+        <input type="number" class="chipValueInput" min="0" step="0.01" placeholder="value" aria-label="Chip value" />
        <button class="holdemBtn holdemBtnSmall holdemBtnDanger removeChipColorBtn">×</button>
    </div>
 </template>
@@ -253,7 +253,7 @@
        </div>
        <div class="addChipsActions">
            <button id="addChipsConfirmBtn" class="holdemBtn holdemBtnAccent" type="button">Add to stack</button>
-            <button id="addChipsCancelBtn" class="holdemBtn holdemBtnGhost" type="button">Cancel</button>
+            <button id="addChipsCancelBtn" data-modal-close class="holdemBtn holdemBtnGhost" type="button">Cancel</button>
        </div>
    </div>
 </div>
@@ -263,7 +263,7 @@
        <div class="seatSheetGrip" aria-hidden="true"></div>
        <div class="rulingsHeader">
            <h2 id="rulingsTitle">Common rulings</h2>
-            <button id="closeRulingsBtn" class="holdemBtn holdemBtnSmall holdemBtnGhost" type="button">Done</button>
+            <button id="closeRulingsBtn" data-modal-close class="holdemBtn holdemBtnSmall holdemBtnGhost" type="button">Done</button>
        </div>

        <p class="rulingsIntro">
@@ -314,7 +314,7 @@
            <span id="seatMenuSubtitle"></span>
        </div>
        <div id="seatMenuActions"></div>
-        <button id="seatMenuCancelBtn" class="holdemBtn holdemBtnGhost" type="button">Cancel</button>
+        <button id="seatMenuCancelBtn" data-modal-close class="holdemBtn holdemBtnGhost" type="button">Cancel</button>
    </div>
 </div>

@@ -324,7 +324,7 @@
        <div class="cardPickerHeader">
            <h2 id="cardPickerTitle"></h2>
            <button id="cardPickerClearBtn" class="holdemBtn holdemBtnSmall" type="button">Clear</button>
-            <button id="cardPickerCloseBtn" class="holdemBtn holdemBtnSmall holdemBtnGhost" type="button">Done</button>
+            <button id="cardPickerCloseBtn" data-modal-close class="holdemBtn holdemBtnSmall holdemBtnGhost" type="button">Done</button>
        </div>
        <div id="cardPickerSlots"></div>
        <div id="cardPickerGrid"></div>
@@ -340,17 +340,17 @@
        <h2 id="confirmTitle"></h2>
        <p id="confirmMessage"></p>
        <div class="confirmActions">
-            <button id="confirmCancelBtn" class="holdemBtn holdemBtnGhost" type="button">Cancel</button>
+            <button id="confirmCancelBtn" data-modal-close class="holdemBtn holdemBtnGhost" type="button">Cancel</button>
            <button id="confirmAcceptBtn" class="holdemBtn holdemBtnDanger" type="button">Confirm</button>
        </div>
    </div>
 </div>

 <div id="potWizardOverlay" hidden>
-    <div id="potWizardModal">
+    <div id="potWizardModal" role="dialog" aria-labelledby="potWizardTitle">
        <div class="potWizardHeader">
-            <h2>Resolve the Pot</h2>
-            <button id="closePotWizardBtn" class="holdemBtn holdemBtnGhost">✕</button>
+            <h2 id="potWizardTitle">Resolve the Pot</h2>
+            <button id="closePotWizardBtn" data-modal-close class="holdemBtn holdemBtnGhost">✕</button>
        </div>
        <div id="potWizardBody"></div>
    </div>
@@ -374,5 +374,6 @@
    <script src="~/js/casino/holdem/shortcuts.js?v=@ViewData["cssVersion"]"></script>
    <script src="~/js/casino/holdem/potWizard.js?v=@ViewData["cssVersion"]"></script>
    <script src="~/js/casino/holdem/handHistoryExport.js?v=@ViewData["cssVersion"]"></script>
+    <script src="~/js/casino/holdem/modal.js?v=@ViewData["cssVersion"]"></script>
    <script src="~/js/casino/holdem/main.js?v=@ViewData["cssVersion"]"></script>
 }
@@ -219,7 +219,11 @@ button,
    padding: 0.6rem 1rem;
    font-size: 0.85rem;
    cursor: pointer;
-    transition: all 0.15s ease;
+    /* Named rather than `all`, so the focus ring isn't animated. With `all` the
+       outline faded in over 150ms, which on keyboard navigation reads as the ring
+       lagging a step behind the Tab key. Nothing else here changes. */
+    transition: background 0.15s ease, border-color 0.15s ease, transform 0.15s ease,
+                box-shadow 0.15s ease, color 0.15s ease, opacity 0.15s ease, filter 0.15s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
@@ -1923,6 +1927,24 @@ body.hasActionBar #holdemSidebar {
    margin-top: 0.1rem;
 }

+/* Tournament-sized amounts. A number has no spaces to break on, so an amount too
+   wide for the 64px puck neither wraps nor ellipsises — it draws straight out over
+   the seat next to it. These step the size down so every digit stays on its own
+   puck. Shrinking rather than abbreviating is deliberate: "$1.25M" would fit more
+   comfortably, but a dealer reading a rounded stack off the felt is a worse failure
+   than a small one, and the exact figure is what the tool is for. */
+.seatPuckStack.puckAmountLong,
+.seatPuckTotal.puckAmountLong {
+    font-size: 0.5rem;
+    letter-spacing: -0.01em;
+}
+
+.seatPuckStack.puckAmountHuge,
+.seatPuckTotal.puckAmountHuge {
+    font-size: 0.44rem;
+    letter-spacing: -0.02em;
+}
+
 .blindsRow {
    display: flex;
    flex-wrap: wrap;
@@ -2672,3 +2694,41 @@ body.hasActionBar #toastHost {
        display: none;
    }
 }
+
+/* ---------- Keyboard focus ----------
+   Three focus rules existed for the whole tool, so tabbing through it relied on
+   whatever ring the browser draws by default — which on these dark, custom-painted
+   controls is close to invisible. `:focus-visible` rather than `:focus` keeps it to
+   keyboard use: a dealer tapping Fold shouldn't be left with a ring on it. */
+.holdemBtn:focus-visible,
+.linkBtn:focus-visible,
+.seatMenuBtn:focus-visible,
+.seatSheetClose:focus-visible,
+.pickerCard:focus-visible,
+.actionBtn:focus-visible,
+.raiseQuickBtn:focus-visible,
+.actionUndo:focus-visible,
+.toastAction:focus-visible,
+.toastClose:focus-visible,
+.potWizardChoice:focus-visible,
+.cardSlot:focus-visible,
+.subPanel summary:focus-visible,
+.seat:focus-visible,
+button:focus-visible,
+[role="button"]:focus-visible,
+input:focus-visible,
+select:focus-visible,
+textarea:focus-visible {
+    outline: 2px solid #7fc4ff;
+    outline-offset: 2px;
+    /* The ring has to sit above the neighbouring seat that overlaps this one. */
+    position: relative;
+    z-index: 3;
+}
+
+/* A sheet with nothing focusable in it takes focus itself so its title is read out.
+   That shouldn't paint a ring around the whole panel. */
+[role="dialog"]:focus,
+[role="alertdialog"]:focus {
+    outline: none;
+}
@@ -39,11 +39,16 @@ const Betting = {
        return this.round((Number(player.amountOverride) || 0) + this.committed(player));
    },

+    // Never below zero. A seat can't have negative chips in front of it, and a typo in
+    // the stack field used to come back as-is — which then flowed into putIn(), where
+    // `Math.min(amount, -50)` moves a negative amount and *adds* chips to the table.
    stackOf(state, player) {
        const own = player.stack;
-        if (own !== null && own !== undefined && String(own).trim() !== "") return this.round(own);
+        if (own !== null && own !== undefined && String(own).trim() !== "") {
+            return Math.max(0, this.round(own));
+        }
        const fallback = Number(state.defaultStack);
-        return Number.isNaN(fallback) ? 0 : this.round(fallback);
+        return Number.isNaN(fallback) ? 0 : Math.max(0, this.round(fallback));
    },

    toCall(state, player) {
@@ -15,6 +15,10 @@ const HandHistoryExport = {
        }
    },

+    // Money columns go in as bare numbers. Written as "$1,250,000.00" they import as
+    // text, so the one thing anybody opens this file to do — total a column and see
+    // who owes what — doesn't work without cleaning every cell first. The commas were
+    // quoted correctly, so the file parsed; it just wouldn't add up.
    toCsv(handHistory, standings = []) {
        const rows = [["Hand #", "Time", "Pot", "Payouts"]];
        // handHistory is stored newest-first; the export reads better oldest-first.
@@ -25,7 +29,7 @@ const HandHistoryExport = {
            rows.push([
                entry.handNumber,
                this.formatTimestamp(entry.timestamp),
-                Money.format(entry.pot),
+                Money.forSheet(entry.pot),
                payouts,
            ]);
        });
@@ -41,12 +45,12 @@ const HandHistoryExport = {
            standings.forEach(row => {
                rows.push([
                    row.name,
-                    Money.format(row.in),
-                    Money.format(row.won),
-                    Money.formatSigned(row.net),
-                    Money.format(row.boughtIn || 0),
-                    Money.format(row.chipsNow || 0),
-                    Money.formatSigned(row.cashPosition || 0),
+                    Money.forSheet(row.in),
+                    Money.forSheet(row.won),
+                    Money.forSheet(row.net),
+                    Money.forSheet(row.boughtIn || 0),
+                    Money.forSheet(row.chipsNow || 0),
+                    Money.forSheet(row.cashPosition || 0),
                ]);
            });
        }
@@ -1,6 +1,10 @@
 document.addEventListener("DOMContentLoaded", () => {
    const state = HoldemState.load();

+    // Focus, Tab-trapping and Escape for every overlay, wired once by watching the
+    // `hidden` attribute they all already toggle.
+    Modal.mount();
+
    // Undo works by swapping the whole table back to a snapshot. `state` is handed out
    // by reference to every module at mount time, so it has to be refilled in place —
    // reassigning the variable would leave the renderer and the betting bar pointing at
@@ -369,6 +373,7 @@ document.addEventListener("DOMContentLoaded", () => {
        if (e.key === "Enter") AddChips.confirm();
    });

+    // Escape is Modal's job now, for this sheet and the five others that never had it.
    const rulingsOverlay = document.getElementById("rulingsOverlay");
    const closeRulings = () => { rulingsOverlay.hidden = true; };
    document.getElementById("openRulingsBtn").addEventListener("click", () => { rulingsOverlay.hidden = false; });
@@ -376,9 +381,6 @@ document.addEventListener("DOMContentLoaded", () => {
    rulingsOverlay.addEventListener("click", e => {
        if (e.target === rulingsOverlay) closeRulings();
    });
-    document.addEventListener("keydown", e => {
-        if (e.key === "Escape" && !rulingsOverlay.hidden) closeRulings();
-    });

    document.getElementById("seatMenuCancelBtn").addEventListener("click", () => SeatMenu.close());
    document.getElementById("seatMenuOverlay").addEventListener("click", e => {
@@ -0,0 +1,147 @@
+// Keyboard and screen-reader behaviour for every overlay in the tool, in one place.
+//
+// There are six of them — seat menu, card picker, add chips, rulings, pot wizard,
+// confirm — opened and closed by five different modules, and each one was missing
+// the same three things: focus never moved into the dialog, Tab walked straight out
+// of it into the page behind the scrim, and Escape did nothing (only the rulings
+// sheet handled it). Measured before this: 0 of 5 moved focus in, 5 of 5 leaked Tab,
+// 1 of 5 closed on Escape.
+//
+// Rather than patch that into five modules, this watches the `hidden` attribute every
+// overlay already toggles. Nothing else had to change, and an overlay added later
+// gets the same behaviour without anyone remembering to wire it up — which is the
+// failure this is fixing in the first place.
+const Modal = {
+    // `:not([hidden])` matters — a sheet that is itself hidden inside an open overlay
+    // must not be a Tab stop.
+    FOCUSABLE: [
+        "a[href]",
+        "button:not([disabled])",
+        'input:not([disabled]):not([type="hidden"])',
+        "select:not([disabled])",
+        "textarea:not([disabled])",
+        '[tabindex]:not([tabindex="-1"])',
+    ].join(","),
+
+    open: [],
+
+    mount() {
+        document.querySelectorAll('[id$="Overlay"]').forEach(overlay => this.watch(overlay));
+        // Capture phase: the dialog gets first refusal on Escape and Tab, before any
+        // table-level shortcut sees them.
+        document.addEventListener("keydown", e => this.onKeyDown(e), true);
+    },
+
+    watch(overlay) {
+        const sync = () => {
+            const isOpen = !overlay.hidden;
+            const known = this.open.some(entry => entry.overlay === overlay);
+            if (isOpen && !known) this.onOpened(overlay);
+            else if (!isOpen && known) this.onClosed(overlay);
+        };
+        new MutationObserver(sync).observe(overlay, { attributes: true, attributeFilter: ["hidden"] });
+        sync();
+    },
+
+    sheetOf(overlay) {
+        return overlay.querySelector('[role="dialog"], [role="alertdialog"]') || overlay.firstElementChild || overlay;
+    },
+
+    focusableIn(overlay) {
+        return [...overlay.querySelectorAll(this.FOCUSABLE)].filter(el => {
+            if (el.closest("[hidden]")) return false;
+            const rect = el.getBoundingClientRect();
+            return rect.width > 0 && rect.height > 0;
+        });
+    },
+
+    onOpened(overlay) {
+        const sheet = this.sheetOf(overlay);
+        // aria-modal is only true while the thing is actually open, so it's set here
+        // rather than baked into the markup.
+        if (sheet) sheet.setAttribute("aria-modal", "true");
+
+        this.open.push({ overlay, returnFocus: document.activeElement });
+
+        // Focus the first real control. A dialog that leaves focus on the button
+        // behind it reads, to a screen reader, as though nothing happened at all.
+        // Content-only sheets get focus on the sheet so the title is announced.
+        const focusable = this.focusableIn(overlay);
+        const target = focusable[0];
+        if (target) {
+            target.focus({ preventScroll: true });
+        } else if (sheet) {
+            if (!sheet.hasAttribute("tabindex")) sheet.setAttribute("tabindex", "-1");
+            sheet.focus({ preventScroll: true });
+        }
+    },
+
+    onClosed(overlay) {
+        const index = this.open.findIndex(entry => entry.overlay === overlay);
+        if (index === -1) return;
+        const [entry] = this.open.splice(index, 1);
+
+        const sheet = this.sheetOf(overlay);
+        if (sheet) sheet.removeAttribute("aria-modal");
+
+        // Put the dealer back where they were. Without this, closing the pot wizard
+        // drops focus to the top of the document and the next Tab starts from the
+        // page header.
+        const back = entry.returnFocus;
+        if (back && back.isConnected && typeof back.focus === "function") {
+            back.focus({ preventScroll: true });
+        }
+    },
+
+    topmost() {
+        return this.open.length ? this.open[this.open.length - 1] : null;
+    },
+
+    // Escape presses the dialog's own cancel/close button rather than just hiding the
+    // overlay, so whatever that button does — resolving the confirm promise, clearing
+    // the add-chips draft — still happens. Only if there isn't one does it hide the
+    // overlay directly.
+    dismiss(overlay) {
+        const closer = overlay.querySelector("[data-modal-close]");
+        if (closer) closer.click();
+        else overlay.hidden = true;
+    },
+
+    onKeyDown(event) {
+        const top = this.topmost();
+        if (!top) return;
+
+        if (event.key === "Escape") {
+            event.preventDefault();
+            event.stopPropagation();
+            this.dismiss(top.overlay);
+            return;
+        }
+
+        if (event.key !== "Tab") return;
+
+        // Keep Tab inside the dialog. Everything behind the scrim is unreachable by
+        // mouse, so letting the keyboard wander back there is a trap with no way out.
+        const focusable = this.focusableIn(top.overlay);
+        if (focusable.length === 0) {
+            event.preventDefault();
+            return;
+        }
+
+        const first = focusable[0];
+        const last = focusable[focusable.length - 1];
+        const active = document.activeElement;
+
+        if (event.shiftKey && (active === first || !top.overlay.contains(active))) {
+            event.preventDefault();
+            last.focus({ preventScroll: true });
+        } else if (!event.shiftKey && (active === last || !top.overlay.contains(active))) {
+            event.preventDefault();
+            first.focus({ preventScroll: true });
+        }
+    },
+};
+
+if (typeof module !== "undefined" && module.exports) {
+    module.exports = Modal;
+}
@@ -25,9 +25,27 @@ const Money = {
        return this.toCents(amount) / 100;
    },

+    // Cents only when there are cents.
+    //
+    // A chip game deals in whole numbers nearly all the time, and a trailing ".00"
+    // is two characters that say nothing — measured at ~22px, against the 64px a
+    // seat puck has to show a stack in. "$1,250,000.00" doesn't fit and wraps;
+    // "$1,250,000" does. Amounts that genuinely carry cents still show them, so a
+    // 25c-blind game reads exactly as it did.
    format(amount) {
        const value = Number(amount) || 0;
-        return `$${value.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 })}`;
+        const hasCents = this.toCents(value) % 100 !== 0;
+        return `$${value.toLocaleString(undefined, {
+            minimumFractionDigits: hasCents ? 2 : 0,
+            maximumFractionDigits: 2,
+        })}`;
+    },
+
+    // The same amount for a spreadsheet rather than for a person: no currency symbol
+    // and no thousands separators, because those are what make a column of money
+    // import as text and refuse to add up.
+    forSheet(amount) {
+        return (this.toCents(amount) / 100).toFixed(2);
    },

    // "+$40.00" / "-$40.00" rather than "$-40.00" — a standings column is read at a
@@ -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();
    },

@@ -261,11 +265,14 @@ const Render = {
        const total = handTotal > 0
            ? handTotal
            : HoldemState.computeContribution(player, this.state.chipLegend, this.state.basePotAmount);
-        node.querySelector(".seatPuckTotal").textContent = total > 0 ? Money.format(total) : "";
+        const totalEl = node.querySelector(".seatPuckTotal");
+        totalEl.textContent = total > 0 ? Money.format(total) : "";
+        this.fitAmount(totalEl);

        const stackEl = node.querySelector(".seatPuckStack");
        const stack = Betting.stackOf(this.state, player);
        stackEl.textContent = !empty && stack > 0 ? Money.format(stack) : "";
+        this.fitAmount(stackEl);

        node.classList.toggle("seatActing", index === this.state.actingSeatIndex);
        node.classList.toggle("seatEmpty", empty);
@@ -274,6 +281,17 @@ const Render = {
        node.classList.toggle("seatLive", player.inHand && !player.folded);
    },

+    // A seat puck is 64px of usable width. A tournament stack doesn't fit in that and,
+    // because the number has no spaces to break on, it doesn't wrap or ellipsise
+    // either — it just draws straight out over the neighbouring seat. Stepping the
+    // font down keeps every digit, which matters: a dealer misreading a stack is a
+    // worse outcome than a small one, so this shrinks rather than abbreviating.
+    fitAmount(el) {
+        const length = (el.textContent || "").length;
+        el.classList.toggle("puckAmountLong", length >= 8 && length < 10);
+        el.classList.toggle("puckAmountHuge", length >= 10);
+    },
+
    // Cheaper than a full renderSeats() — used after edits so the seat editor's inputs
    // (which live in a separate panel) never lose focus.
    refreshPuck(index) {
@@ -689,24 +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);
@@ -717,8 +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);
    },
 };

@@ -32,14 +32,12 @@ const Shortcuts = {
        return tag === "INPUT" || tag === "TEXTAREA" || tag === "SELECT" || el.isContentEditable;
    },

-    // An overlay owns the keyboard while it's up: the confirm dialog already binds
-    // Enter and Escape, and the card picker and seat menu are modal.
+    // An overlay owns the keyboard while it's up. Asking the document which overlays
+    // are open, rather than listing them, means a sheet added later can't quietly
+    // start letting "f" fold the table behind it — the same reason Modal watches for
+    // them instead of being told about each one.
    overlayOpen() {
-        return ["confirmOverlay", "potWizardOverlay", "cardPickerOverlay", "seatMenuOverlay", "rulingsOverlay", "addChipsOverlay"]
-            .some(id => {
-                const el = document.getElementById(id);
-                return el && !el.hidden;
-            });
+        return [...document.querySelectorAll('[id$="Overlay"]')].some(el => !el.hidden);
    },

    onKey(e) {
@@ -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"));
+    });
+});
@@ -18,6 +18,11 @@ const Money = load("money");
 const PotCalculator = load("potCalculator");
 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"));
@@ -68,6 +73,8 @@ function contributions(state) {

 module.exports = {
    Money,
+    Render,
+    HandHistoryExport,
    PotCalculator,
    SplitCalculator,
    Betting,
@@ -0,0 +1,126 @@
+const { test, describe } = require("node:test");
+const assert = require("node:assert/strict");
+const { Money, HandHistoryExport } = require("./load");
+
+describe("Money.format", () => {
+    test("whole amounts drop the pointless cents", () => {
+        assert.equal(Money.format(12), "$12");
+        assert.equal(Money.format(450), "$450");
+        assert.equal(Money.format(1250000), "$1,250,000");
+        assert.equal(Money.format(0), "$0");
+    });
+
+    test("amounts that carry cents still show them", () => {
+        assert.equal(Money.format(12.5), "$12.50");
+        assert.equal(Money.format(0.25), "$0.25");
+        assert.equal(Money.format(3.01), "$3.01");
+    });
+
+    test("a quarter-blind game reads exactly as it did", () => {
+        // The case that would be ruined by dropping cents unconditionally.
+        [0.25, 0.5, 1.75, 12.05].forEach(v => {
+            assert.match(Money.format(v), /\.\d\d$/, `${v} lost its cents`);
+        });
+    });
+
+    test("floating-point dust doesn't invent cents", () => {
+        assert.equal(Money.format(0.1 + 0.2), "$0.30");
+        assert.equal(Money.format(1.0000000001), "$1");
+    });
+
+    test("signed amounts put the sign out front, both scales", () => {
+        assert.equal(Money.formatSigned(87500), "+$87,500");
+        assert.equal(Money.formatSigned(-87500), "-$87,500");
+        assert.equal(Money.formatSigned(-12.5), "-$12.50");
+        assert.equal(Money.formatSigned(0), "$0");
+    });
+
+    test("rubbish in doesn't produce rubbish out", () => {
+        assert.equal(Money.format(null), "$0");
+        assert.equal(Money.format(undefined), "$0");
+        assert.equal(Money.format("nonsense"), "$0");
+    });
+});
+
+describe("Money.forSheet", () => {
+    test("a bare number a spreadsheet will add up", () => {
+        assert.equal(Money.forSheet(1250000), "1250000.00");
+        assert.equal(Money.forSheet(12.5), "12.50");
+        assert.equal(Money.forSheet(-87500), "-87500.00");
+    });
+
+    test("no currency symbol and no thousands separators", () => {
+        const written = Money.forSheet(1234567.89);
+        assert.ok(!written.includes("$"), "a $ makes the cell text");
+        assert.ok(!written.includes(","), "a comma makes the cell text");
+        assert.equal(Number(written), 1234567.89, "and it parses straight back to a number");
+    });
+});
+
+describe("the exported CSV", () => {
+    const history = [
+        { handNumber: 2, timestamp: 0, pot: 1250000, payouts: [{ id: "a", label: "Alexandra", amount: 1250000 }] },
+        { handNumber: 1, timestamp: 0, pot: 24.5, payouts: [{ id: "b", label: "Bob", amount: 24.5 }] },
+    ];
+    const standings = [
+        { id: "a", name: "Alexandra", in: 1250000, won: 1250000, net: 0, boughtIn: 3200000, chipsNow: 3200000, cashPosition: 0 },
+        { id: "b", name: "Bob", in: 24.5, won: 0, net: -24.5, boughtIn: 100, chipsNow: 75.5, cashPosition: -24.5 },
+    ];
+
+    // Splitting on commas isn't good enough: the timestamp column legitimately holds
+    // one ("1/1/1970, 5:00:00 PM") and is quoted for exactly that reason.
+    const splitRow = line => {
+        const fields = [];
+        let field = "";
+        let quoted = false;
+        for (let i = 0; i < line.length; i++) {
+            const c = line[i];
+            if (quoted) {
+                if (c === '"' && line[i + 1] === '"') { field += '"'; i++; }
+                else if (c === '"') quoted = false;
+                else field += c;
+            } else if (c === '"') quoted = true;
+            else if (c === ",") { fields.push(field); field = ""; }
+            else field += c;
+        }
+        fields.push(field);
+        return fields;
+    };
+
+    test("every money cell parses as a number", () => {
+        const csv = HandHistoryExport.toCsv(history, standings);
+        const lines = csv.split("\r\n");
+
+        lines.slice(1, 3).forEach(line => {
+            const cell = splitRow(line)[2]; // Pot
+            assert.ok(cell !== "" && !Number.isNaN(Number(cell)), `pot cell "${cell}" isn't a number`);
+        });
+
+        // Standings rows: every column after the name has to be numeric.
+        const standingsStart = lines.findIndex(l => l.startsWith("Player,"));
+        lines.slice(standingsStart + 1).filter(Boolean).forEach(line => {
+            splitRow(line).slice(1).forEach(cell => {
+                assert.ok(cell !== "" && !Number.isNaN(Number(cell)), `standings cell "${cell}" isn't a number`);
+            });
+        });
+    });
+
+    test("a million-dollar pot doesn't need quoting any more", () => {
+        const csv = HandHistoryExport.toCsv(history, []);
+        assert.ok(csv.includes("1250000.00"), "written plainly");
+        assert.ok(!csv.includes('"$1,250,000'), "not as a quoted, unsummable string");
+    });
+
+    test("names and payout descriptions stay human", () => {
+        const csv = HandHistoryExport.toCsv(history, standings);
+        assert.ok(csv.includes("Alexandra"), "the name column is still a name");
+        assert.ok(csv.includes("Alexandra: $1,250,000"), "the payout column still reads like a sentence");
+    });
+
+    test("a name with a comma is still quoted properly", () => {
+        const csv = HandHistoryExport.toCsv([], [
+            { id: "x", name: "Smith, John", in: 0, won: 0, net: 0, boughtIn: 0, chipsNow: 0, cashPosition: 0 },
+        ]);
+        assert.ok(csv.includes('"Smith, John"'), "the CSV escaping still applies where it's needed");
+    });
+});
@@ -0,0 +1,144 @@
+// Values a dealer can actually produce with a typo, and the ones a corrupted save
+// can produce on its own. None of these should be able to move chips.
+const { test, describe } = require("node:test");
+const assert = require("node:assert/strict");
+const { Betting, HoldemState, makeTable, chipsOnTable } = require("./load");
+
+describe("a stack can never go negative", () => {
+    test("a mistyped negative stack reads as empty, not as owing chips", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+        state.seats[0].stack = -50;
+        assert.equal(Betting.stackOf(state, state.seats[0]), 0);
+    });
+
+    test("a negative stack can't be bet with", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+        state.seats[0].stack = -50;
+        const before = state.seats.reduce((s, p) => s + Math.max(0, Number(p.stack) || 0), 0);
+
+        const moved = Betting.putIn(state, 0, 25);
+
+        assert.equal(moved, 0, "nothing moves out of an empty stack");
+        assert.ok(Betting.stackOf(state, state.seats[0]) >= 0);
+        assert.equal(state.seats[0].committed, 0, "and nothing appears in front of them");
+        assert.ok(state.seats.reduce((s, p) => s + Math.max(0, Number(p.stack) || 0), 0) <= before);
+    });
+
+    test("a negative table default doesn't hand everyone a negative stack", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+        state.seats.forEach(p => { p.stack = null; });
+        state.defaultStack = -100;
+        state.seats.forEach(p => assert.equal(Betting.stackOf(state, p), 0));
+    });
+
+    test("a negative stack doesn't make a player look like they can still bet", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+        state.seats[0].stack = -50;
+        assert.ok(!Betting.seatsWithChips(state).some(s => s.index === 0));
+    });
+});
+
+describe("blinds that can't be posted", () => {
+    test("negative blinds post nothing rather than paying players to sit down", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+        state.smallBlind = -5;
+        state.bigBlind = -10;
+        const before = chipsOnTable(state);
+
+        Betting.beginHand(state);
+
+        state.seats.forEach(p => assert.equal(p.committed, 0));
+        assert.equal(chipsOnTable(state), before);
+    });
+
+    test("an unreadable blind doesn't wedge the hand", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2] });
+        state.bigBlind = NaN;
+        state.smallBlind = 1;
+
+        Betting.beginHand(state);
+
+        assert.ok(Number.isFinite(state.currentBet), "the bet to match is still a number");
+        assert.ok(!Number.isNaN(Betting.potSoFar(state)));
+    });
+
+    test("blinds nobody can cover put those players all-in and move on", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2], stack: 10 });
+        state.smallBlind = 500;
+        state.bigBlind = 1000;
+        const before = chipsOnTable(state);
+
+        Betting.beginHand(state);
+
+        assert.equal(chipsOnTable(state), before, "no chips invented covering a blind");
+        state.seats.forEach(p => assert.ok((Number(p.stack) || 0) >= 0));
+        assert.ok(state.actingSeatIndex === null || state.seats[state.actingSeatIndex].inHand);
+    });
+});
+
+describe("a saved table that comes back damaged", () => {
+    test("unreadable storage falls back to a fresh table", () => {
+        // load() has to survive whatever is in localStorage, because the alternative
+        // is a dealer opening the tool mid-session to a blank screen.
+        const original = globalThis.localStorage;
+        globalThis.localStorage = {
+            getItem: () => "{not json at all",
+            setItem: () => {},
+            removeItem: () => {},
+        };
+        const state = HoldemState.load();
+        globalThis.localStorage = original;
+
+        assert.equal(state.seats.length, HoldemState.DEFAULT_SEAT_COUNT);
+        assert.equal(state.handNumber, 1);
+    });
+
+    test("a save missing its seats is treated as no save at all", () => {
+        const original = globalThis.localStorage;
+        globalThis.localStorage = {
+            getItem: () => JSON.stringify({ handNumber: 7, smallBlind: 3 }),
+            setItem: () => {},
+            removeItem: () => {},
+        };
+        const state = HoldemState.load();
+        globalThis.localStorage = original;
+
+        assert.ok(Array.isArray(state.seats) && state.seats.length > 0);
+    });
+
+    test("a save from before a field existed gets the field, not undefined", () => {
+        const original = globalThis.localStorage;
+        globalThis.localStorage = {
+            getItem: () => JSON.stringify({
+                seats: [{ id: "a", name: "Ann", inHand: true }, { id: "b", name: "Ben", inHand: true }],
+                handNumber: 4,
+            }),
+            setItem: () => {},
+            removeItem: () => {},
+        };
+        const state = HoldemState.load();
+        globalThis.localStorage = original;
+
+        assert.equal(state.blindOverride, null);
+        assert.equal(state.street, "preflop");
+        state.seats.forEach(p => {
+            assert.equal(p.committed, 0);
+            assert.equal(p.hasActed, false);
+            assert.equal(p.buyIns, 0);
+        });
+        // And it has to be playable, not just parseable.
+        assert.doesNotThrow(() => Betting.beginHand(state));
+    });
+
+    test("storage that refuses to be written doesn't take the table down", () => {
+        const original = globalThis.localStorage;
+        globalThis.localStorage = {
+            getItem: () => null,
+            setItem: () => { throw new Error("QuotaExceededError"); },
+            removeItem: () => {},
+        };
+        const state = HoldemState.createDefault();
+        assert.doesNotThrow(() => HoldemState.save(state), "a full disk must not break the hand in progress");
+        globalThis.localStorage = original;
+    });
+});