normalization optimized

app/static/js/asset-duplicates.js

@@ -47,9 +47,9 @@
     }
 
     function normalize(value) {
-      const sharedNormalize = window.AssetManagerNormalizeSearchText;
-      if (typeof sharedNormalize === 'function') {
-        return sharedNormalize(value, {
+      const sharedKey = window.AssetManagerGermanSearchKey;
+      if (typeof sharedKey === 'function') {
+        return sharedKey(value, {
           caseSensitive: !caseInsensitive.checked,
           collapseWhitespace: true
         });

app/static/js/asset-inventory.js

@@ -11,11 +11,11 @@
   const table = document.getElementById('software-inventory-table');
   if (filter && table) {
     filter.addEventListener('input', () => {
-      const normalize = window.AssetManagerNormalizeSearchText ||
-        ((value) => String(value || '').toLocaleLowerCase());
-      const needle = normalize(filter.value.trim());
+      const matches = window.AssetManagerSearchTextMatches ||
+        ((value, term) => String(value || '').toLocaleLowerCase().includes(String(term || '').toLocaleLowerCase()));
+      const needle = filter.value.trim();
       table.querySelectorAll('tbody tr').forEach((row) => {
-        row.hidden = Boolean(needle) && !normalize(row.textContent).includes(needle);
+        row.hidden = Boolean(needle) && !matches(row.textContent, needle);
       });
     });
   }

app/static/js/table-tools.js

@@ -4,28 +4,52 @@
     const collapseWhitespace = Boolean(options.collapseWhitespace);
     let text = String(value ?? '');
 
-    // Preserve the common German transliterations before Unicode accent
-    // folding so searches treat umlauts and their ASCII spellings equally.
-    text = text
-      .replace(/Ä/g, 'Ae')
-      .replace(/Ö/g, 'Oe')
-      .replace(/Ü/g, 'Ue')
-      .replace(/ä/g, 'ae')
-      .replace(/ö/g, 'oe')
-      .replace(/ü/g, 'ue')
-      .replace(/ẞ/g, 'SS')
-      .replace(/ß/g, 'ss')
-      .normalize('NFKD')
-      .replace(/[\u0300-\u036f]/g, '');
-
     if (collapseWhitespace) text = text.trim().replace(/\s+/g, ' ');
     if (!caseSensitive) text = text.toLocaleLowerCase();
-    return text;
+
+    const protectedGerman = text
+      .replace(/ä/g, '\uE000')
+      .replace(/ö/g, '\uE001')
+      .replace(/ü/g, '\uE002')
+      .replace(/ß/g, '\uE003');
+
+    return protectedGerman
+      .normalize('NFKD')
+      .replace(/[\u0300-\u036f]/g, '')
+      .replace(/\uE000/g, 'ä')
+      .replace(/\uE001/g, 'ö')
+      .replace(/\uE002/g, 'ü')
+      .replace(/\uE003/g, 'ß');
+  }
+
+  function germanSearchKey(value, options = {}) {
+    let text = normalizeSearchText(value, options);
+
+    // Mark only plausible ASCII umlaut spellings. The marker keeps a real or
+    // transliterated umlaut distinct from natural letter pairs in words such
+    // as "Bauer", "teuer" and "euer".
+    text = text.replace(/(^|[^aeiouäöü])([aou])e/g, '$1$2~e');
+
+    return text
+      .replace(/ä/g, 'a~e')
+      .replace(/ö/g, 'o~e')
+      .replace(/ü/g, 'u~e')
+      .replace(/ß/g, 's~s');
+  }
+
+  function searchTextMatches(value, term, options = {}) {
+    const directValue = normalizeSearchText(value, options);
+    const directTerm = normalizeSearchText(term, options);
+    if (!directTerm) return true;
+    if (directValue.includes(directTerm)) return true;
+    return germanSearchKey(value, options).includes(germanSearchKey(term, options));
   }
 
   // Standalone filters and duplicate detection use the exact same comparison
   // rules as the generic table filters.
   window.AssetManagerNormalizeSearchText = normalizeSearchText;
+  window.AssetManagerGermanSearchKey = germanSearchKey;
+  window.AssetManagerSearchTextMatches = searchTextMatches;
 
   const collator = new Intl.Collator(document.documentElement.lang || 'de', {
     numeric: true,
@@ -387,7 +411,7 @@
       const active = filterDefinitions
         .map(definition => ({
           definition,
-          term: normalizeSearchText(definition.input?.value.trim() || '')
+          term: definition.input?.value.trim() || ''
         }))
         .filter(item => item.term);
 
@@ -415,7 +439,7 @@
           if (definition.numericFilter) {
             return !numericFilterMatches(value, term);
           }
-          return !normalizeSearchText(value).includes(term);
+          return !searchTextMatches(value, term);
         });
 
         row.hidden = hidden;