prevent doubles

index.html

@@ -396,6 +396,11 @@
                 width: 200px;
             }
 
+            /* Hidden code column — stores raw scan code for duplicate checking */
+            .col-code {
+                display: none;
+            }
+
             tbody tr {
                 border-bottom: 1px solid var(--card);
                 animation: rowIn 0.28s ease-out;
@@ -881,6 +886,7 @@
                             <th>Country</th>
                             <th>Name</th>
                             <th>Tag</th>
+                            <th class="col-code">Code</th>
                         </tr>
                     </thead>
                     <tbody id="tableBody"></tbody>
@@ -1201,6 +1207,15 @@
                 });
             }
 
+            // ── Duplicate check ──────────────────────────────────────────────────────
+            function isDuplicate(code) {
+                const cells = tableBody.querySelectorAll(".col-code");
+                for (const cell of cells) {
+                    if (cell.textContent === code.trim()) return true;
+                }
+                return false;
+            }
+
             // ── Submit Scan ──────────────────────────────────────────────────────────
             async function submitScan(code) {
                 const user = userSelect.value;
@@ -1216,6 +1231,17 @@
                     return;
                 }
 
+                // Duplicate check against already-scanned codes in the table
+                if (isDuplicate(code)) {
+                    showToast(
+                        "⚠️ Already scanned: " + code.trim(),
+                        "fail",
+                        4000,
+                    );
+                    scanInput.select();
+                    return;
+                }
+
                 showBanner("Looking up package…", "loading");
 
                 try {
@@ -1253,7 +1279,7 @@
                         return;
                     }
                     hideBanner();
-                    addRow(item);
+                    addRow(item, code);
                     showToast(
                         "✓ Added: " + (item.name || item.producttag || code),
                         "ok",
@@ -1273,8 +1299,8 @@
                 }
             }
 
-            // ── Table Row ────────────────────────────────────────────────────────────
-            function addRow(item) {
+            // ── Table Row ───────────────────────────────────────────────────────────────────
+            function addRow(item, code) {
                 emptyState.style.display = "none";
                 scanCount++;
                 countPill.textContent =
@@ -1286,6 +1312,7 @@
         <td><span class="country-badge">${esc(item.country || "—")}</span></td>
         <td class="name-cell">${esc(item.name || "—")}</td>
         <td><span class="tag-pill" title="${esc(item.producttag || "")}">${esc(item.producttag || "—")}</span></td>
+        <td class="col-code">${esc(code.trim())}</td>
       `;
                 // Newest row at the top
                 tableBody.insertBefore(tr, tableBody.firstChild);