feat: infinite scroll op zoekresultaten — append-based batch loading (50 per batch)

- renderZoeken toont alleen eerste 50 items, geen DOM overload meer
- IntersectionObserver laadt volgende batches via append (behoudt scrollpositie)
- Event delegation voor openAddToMealForMoment (werkt met dynamisch geladen items)
- Pagination reset bij nieuw zoekopdracht, categorie-filter, en tab-switch
- Sentinel-element onder foodList als IntersectionObserver target
- searchSentinel/sentinel CSS + searchLoading styling

index.html

@@ -252,6 +252,19 @@ body {
   list-style: none;
 }
 
+.search-sentinel {
+  height: 1px;
+  width: 100%;
+}
+
+.search-loading {
+  display: flex;
+  justify-content: center;
+  padding: 16px;
+  color: var(--text-muted);
+  font-size: var(--font-sm);
+}
+
 .food-item {
   background: var(--white);
   border-radius: var(--radius-sm);
@@ -2048,6 +2061,7 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
       <div class="results-section">
         <div class="results-count" id="resultsCount"></div>
         <ul class="food-list" id="foodList"></ul>
+        <div id="searchSentinel" class="search-sentinel"></div>
         <div class="loading hidden" id="loadingState">
           <div class="loading-spinner"></div>
           <div>Voedingsmiddelen laden...</div>
@@ -2355,6 +2369,9 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
   let searchIndex = null;   // Map<item, expanded search tokens string>
   let dataLoaded = false;
   let maaltijden = [];       // [{ id, naam, items: [{item, portie}, ...], khTotaal }]
+  const SEARCH_PAGE_SIZE = 50;
+  let searchVisibleCount = SEARCH_PAGE_SIZE;
+  let searchObserver = null;
 
   // ===== Utility Functions =====
   function formatDate(d) {
@@ -2671,16 +2688,17 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
   // ===== Rendering =====
   function renderZoeken() {
     if (!dataLoaded) return;
+    if (activeTab !== 'zoeken') return;
 
     const items = getFilteredItems();
     const listEl = document.getElementById('foodList');
     const countEl = document.getElementById('resultsCount');
     const emptyEl = document.getElementById('emptyState');
-    const container = document.getElementById('tabZoeken');
+    const sentinelEl = document.getElementById('searchSentinel');
-    const errorEl = document.getElementById('errorState');
 
-    // Make sure zoeken tab is visible if active
+    // Reset pagination on new search/filter
-    if (activeTab !== 'zoeken') return;
+    searchVisibleCount = SEARCH_PAGE_SIZE;
+    disconnectSearchObserver();
 
     // Show results count
     countEl.textContent = items.length === 0
@@ -2691,35 +2709,110 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
     if (items.length === 0) {
       listEl.innerHTML = '';
       emptyEl.classList.remove('hidden');
-    } else {
+      sentinelEl.classList.add('hidden');
-      emptyEl.classList.add('hidden');
+      return;
-      listEl.innerHTML = items.map((item, idx) => {
-        const kh = parseKh(item.kh);
-        return `
-          <li class="food-item" data-index="${voedingsmiddelen.indexOf(item)}" style="--i:${idx}" role="button" tabindex="0">
-            <div class="food-item-left">
-              <div class="food-item-name">${escapeHtml(displayNaam(item.naam))}</div>
-              <div class="food-item-cat">${escapeHtml(item.cat)}</div>
-            </div>
-            <div class="food-item-right">
-              <div class="food-item-kh">${formatKh(kh)}</div>
-              <div class="food-item-unit">g kh / 100g</div>
-            </div>
-            <span class="food-item-arrow">›</span>
-          </li>
-        `;
-      }).join('');
-
-      // Add click handlers
-      listEl.querySelectorAll('.food-item').forEach(el => {
-        el.addEventListener('click', () => {
-          const idx = parseInt(el.dataset.index);
-          if (idx >= 0 && idx < voedingsmiddelen.length) {
-            showDetail(voedingsmiddelen[idx]);
-          }
-        });
-      });
     }
+
+    emptyEl.classList.add('hidden');
+
+    // Render first batch
+    const batch = items.slice(0, SEARCH_PAGE_SIZE);
+    listEl.innerHTML = renderFoodItemsHtml(batch, 0);
+    attachFoodItemHandlers(listEl);
+
+    // Setup infinite scroll if more items exist
+    if (items.length > SEARCH_PAGE_SIZE) {
+      sentinelEl.classList.remove('hidden');
+      setupSearchObserver(items);
+    } else {
+      sentinelEl.classList.add('hidden');
+      disconnectSearchObserver();
+    }
+  }
+
+  function renderFoodItemsHtml(items, startIndex) {
+    return items.map((item, idx) => {
+      const globalIdx = startIndex + idx;
+      const kh = parseKh(item.kh);
+      return `
+        <li class="food-item" data-index="${voedingsmiddelen.indexOf(item)}" style="--i:${globalIdx}" role="button" tabindex="0">
+          <div class="food-item-left">
+            <div class="food-item-name">${escapeHtml(displayNaam(item.naam))}</div>
+            <div class="food-item-cat">${escapeHtml(item.cat)}</div>
+          </div>
+          <div class="food-item-right">
+            <div class="food-item-kh">${formatKh(kh)}</div>
+            <div class="food-item-unit">g kh / 100g</div>
+          </div>
+          <span class="food-item-arrow">›</span>
+        </li>
+      `;
+    }).join('');
+  }
+
+  function attachFoodItemHandlers(listEl) {
+    listEl.querySelectorAll('.food-item').forEach(el => {
+      // Avoid double handlers on re-render edge cases
+      if (el._clickAttached) return;
+      el._clickAttached = true;
+      el.addEventListener('click', () => {
+        const idx = parseInt(el.dataset.index);
+        if (idx >= 0 && idx < voedingsmiddelen.length) {
+          showDetail(voedingsmiddelen[idx]);
+        }
+      });
+    });
+  }
+
+  function setupSearchObserver(allItems) {
+    disconnectSearchObserver();
+    const sentinel = document.getElementById('searchSentinel');
+    if (!sentinel) return;
+
+    searchObserver = new IntersectionObserver((entries) => {
+      if (entries[0].isIntersecting) {
+        appendSearchBatch(allItems);
+      }
+    }, { rootMargin: '200px' });
+
+    searchObserver.observe(sentinel);
+  }
+
+  function appendSearchBatch(allItems) {
+    const listEl = document.getElementById('foodList');
+    const sentinelEl = document.getElementById('searchSentinel');
+    if (!listEl || !sentinelEl) return;
+
+    const remaining = allItems.length - searchVisibleCount;
+    if (remaining <= 0) {
+      disconnectSearchObserver();
+      sentinelEl.classList.add('hidden');
+      return;
+    }
+
+    const batchSize = Math.min(SEARCH_PAGE_SIZE, remaining);
+    const batch = allItems.slice(searchVisibleCount, searchVisibleCount + batchSize);
+    listEl.insertAdjacentHTML('beforeend', renderFoodItemsHtml(batch, searchVisibleCount));
+    attachFoodItemHandlers(listEl);
+    searchVisibleCount += batchSize;
+
+    // All items loaded — hide sentinel and disconnect
+    if (searchVisibleCount >= allItems.length) {
+      disconnectSearchObserver();
+      sentinelEl.classList.add('hidden');
+    }
+  }
+
+  function disconnectSearchObserver() {
+    if (searchObserver) {
+      searchObserver.disconnect();
+      searchObserver = null;
+    }
+  }
+
+  function resetSearchPagination() {
+    searchVisibleCount = SEARCH_PAGE_SIZE;
+    disconnectSearchObserver();
   }
 
   function renderProgressBar(totaal) {
@@ -3151,21 +3244,21 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
     // Store the target moment so next food tap adds to it
     window._targetMoment = momentId;
 
-    // Override food item click behavior temporarily
+    // Use event delegation so dynamically loaded items also work
     const listEl = document.getElementById('foodList');
-    listEl.querySelectorAll('.food-item').forEach(el => {
+    const handler = (e) => {
-      const origClick = el.onclick;
+      const itemEl = e.target.closest('.food-item');
-      el.addEventListener('click', function handler(e) {
+      if (!itemEl) return;
-        const idx = parseInt(el.dataset.index);
+      const idx = parseInt(itemEl.dataset.index);
-        if (idx >= 0 && idx < voedingsmiddelen.length && window._targetMoment) {
+      if (idx >= 0 && idx < voedingsmiddelen.length && window._targetMoment) {
-          e.stopPropagation();
+        e.stopPropagation();
-          e.preventDefault();
+        e.preventDefault();
-          showAddToMeal(voedingsmiddelen[idx], window._targetMoment);
+        showAddToMeal(voedingsmiddelen[idx], window._targetMoment);
-          window._targetMoment = null;
+        window._targetMoment = null;
-          el.removeEventListener('click', handler);
+        listEl.removeEventListener('click', handler);
-        }
+      }
-      }, { once: true });
+    };
-    });
+    listEl.addEventListener('click', handler);
   }
 
   function addToMeal(item, portie, momentId) {
@@ -3546,10 +3639,13 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
     setTimeout(() => mainContent.classList.remove('page-transition'), 350);
 
     if (tab === 'zoeken') {
+      resetSearchPagination();
       renderZoeken();
     } else if (tab === 'dagboek') {
+      disconnectSearchObserver();
       renderDagboek();
     } else if (tab === 'maaltijden') {
+      disconnectSearchObserver();
       renderMaaltijden();
     }
   }
@@ -4599,6 +4695,7 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
     searchInput.addEventListener('input', () => {
       searchQuery = searchInput.value;
       searchClear.classList.toggle('visible', searchQuery.length > 0);
+      resetSearchPagination();
       renderZoeken();
     });
 
@@ -4606,6 +4703,7 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
       searchInput.value = '';
       searchQuery = '';
       searchClear.classList.remove('visible');
+      resetSearchPagination();
       renderZoeken();
       searchInput.focus();
     });
@@ -4619,6 +4717,7 @@ button:active, .btn:active, .meal-card-main:active, .dagboek-item:active, .food-
       btn.classList.add('active');
 
       selectedCategory = btn.dataset.cat || null;
+      resetSearchPagination();
       renderZoeken();
     });