feat: refactor recipe parsing logic; replace regex literals with constants for improved readability and maintainability

backend/src/common/utils/recipe-parser.ts

@@ -21,6 +21,26 @@ export interface ParsedRecipe {
   ingredients: ParsedIngredient[];
 }
 
+// ============================================================================
+// Module-level constants (hoisted for performance)
+// ============================================================================
+
+const KNOWN_UNITS = new Set([
+  'g', 'kg', 'hg', 'mg', 'ml', 'dl', 'l', 'tl',
+  'st', 'tsk', 'msk', 'krm', 'matsled', 'tesled',
+  'pris', 'portion', 'port', 'burk', 'förp', 'paket', 'efter smak', 'klyfta',
+]);
+
+const H1_RE = /^#\s+/;
+const H2_RE = /^##\s+/;
+const INGREDIENT_HEADING_RE = /ingrediens/;
+const INSTRUCTION_HEADING_RE = /instruktion|tillagning|gör så här|steg|tillväg|metod/;
+const BULLET_RE = /^[-*]\s+/;
+const PAREN_NOTE_RE = /\(([^)]+)\)\s*$/;
+const FRACTION_RE = /^(\d+)?\s*(\d+)\s*\/\s*([\d.]+)\s+(\S+)\s+(.+)$/;
+const QTY_UNIT_NAME_RE = /^(\d+(?:[.,]\d+)?)\s+(\S+)\s+(.+)$/;
+const QTY_NAME_RE = /^(\d+(?:[.,]\d+)?)\s+(.+)$/;
+
 // ============================================================================
 // Parser Functions
 // ============================================================================
@@ -56,18 +76,18 @@ export function parseRecipeMarkdown(markdown: string): ParsedRecipe {
     const trimmed = line.trim();
 
     // H1 — receptnamn
-    if (/^#\s+/.test(trimmed) && !trimmed.startsWith('##')) {
+    if (H1_RE.test(trimmed) && !trimmed.startsWith('##')) {
-      name = trimmed.replace(/^#\s+/, '').trim();
+      name = trimmed.replace(H1_RE, '').trim();
       currentSection = 'description';
       continue;
     }
 
     // H2 — sektionsrubriker
-    if (/^##\s+/.test(trimmed)) {
+    if (H2_RE.test(trimmed)) {
-      const heading = trimmed.replace(/^##\s+/, '').trim().toLowerCase();
+      const heading = trimmed.replace(H2_RE, '').trim().toLowerCase();
-      if (/ingrediens/.test(heading)) {
+      if (INGREDIENT_HEADING_RE.test(heading)) {
         currentSection = 'ingredients';
-      } else if (/instruktion|tillagning|gör så här|steg|tillväg|metod/.test(heading)) {
+      } else if (INSTRUCTION_HEADING_RE.test(heading)) {
         currentSection = 'instructions';
       } else {
         currentSection = 'none';
@@ -84,8 +104,8 @@ export function parseRecipeMarkdown(markdown: string): ParsedRecipe {
         break;
 
       case 'ingredients':
-        if (/^[-*]\s+/.test(trimmed)) {
+        if (BULLET_RE.test(trimmed)) {
-          const ingredientText = trimmed.replace(/^[-*]\s+/, '');
+          const ingredientText = trimmed.replace(BULLET_RE, '');
           ingredients.push(parseIngredientLine(ingredientText));
         }
         break;
@@ -116,82 +136,45 @@ export function parseRecipeMarkdown(markdown: string): ParsedRecipe {
 function parseIngredientLine(text: string): ParsedIngredient {
   const trimmed = text.trim();
 
-  // Kända enheter
-  const knownUnits = [
-    'g', 'kg', 'hg', 'mg', 'ml', 'dl', 'l', 'tl',
-    'st', 'tsk', 'msk', 'krm', 'matsled', 'tesled',
-    'pris', 'portion', 'port', 'burk', 'förp', 'paket', 'efter smak', 'klyfta',
-  ];
-
   // Extrahera eventuell parentes-not i slutet
   let note: string | null = null;
   let main = trimmed;
-  const parenMatch = trimmed.match(/\(([^)]+)\)\s*$/);
+  const parenMatch = trimmed.match(PAREN_NOTE_RE);
   if (parenMatch) {
     note = parenMatch[1].trim();
     main = trimmed.slice(0, parenMatch.index).trim();
   }
 
-  // Försök matcha bråk först: "1 1/2 dl crème fraiche" eller "1/2 dl"
+  // Försök matcha bråk först: "1 1/2 dl crème fraiche" eller "1/2 dl mjölk"
-  const fractionMatch = main.match(/^(\d+)?\s*(\d+)\s*\/\s*([\d.]+)\s+(\S+)\s+(.*)$/);
+  const fractionMatch = main.match(FRACTION_RE);
   if (fractionMatch) {
-    let quantity = 0;
+    const whole = fractionMatch[1] ? parseFloat(fractionMatch[1]) : 0;
-    if (fractionMatch[1]) {
+    const quantity = whole + parseFloat(fractionMatch[2]) / parseFloat(fractionMatch[3]);
-      quantity = parseFloat(fractionMatch[1]) + parseFloat(fractionMatch[2]) / parseFloat(fractionMatch[3]);
-    } else {
-      quantity = parseFloat(fractionMatch[2]) / parseFloat(fractionMatch[3]);
-    }
     const candidateUnit = fractionMatch[4].toLowerCase();
-    if (knownUnits.includes(candidateUnit)) {
+    if (KNOWN_UNITS.has(candidateUnit)) {
-      return {
+      return { quantity, unit: candidateUnit, rawName: fractionMatch[5].trim(), note };
-        quantity,
-        unit: candidateUnit,
-        rawName: fractionMatch[5].trim(),
-        note,
-      };
     }
   }
 
   // Försök matcha "kvantitet enhet namn" — t.ex. "400 g kycklingfilé" eller "2.5 dl grädde"
-  const fullMatch = main.match(/^(\d+(?:[.,]\d+)?)\s+(\S+)\s+(.+)$/);
+  const fullMatch = main.match(QTY_UNIT_NAME_RE);
   if (fullMatch) {
     const candidateUnit = fullMatch[2].toLowerCase();
-    // Validera att det andra ordet är en känd enhet
+    if (KNOWN_UNITS.has(candidateUnit)) {
-    if (knownUnits.includes(candidateUnit)) {
+      return { quantity: parseNumber(fullMatch[1]), unit: candidateUnit, rawName: fullMatch[3].trim(), note };
-      return {
-        quantity: parseNumber(fullMatch[1]),
-        unit: candidateUnit,
-        rawName: fullMatch[3].trim(),
-        note,
-      };
     }
-    // Om inte känd enhet, behandla som "kvantitet namn" utan enhet
+    // Inte känd enhet — behandla "kvantitet ord1 ord2..." utan enhet
-    return {
+    return { quantity: parseNumber(fullMatch[1]), unit: 'st', rawName: fullMatch[2] + ' ' + fullMatch[3], note };
-      quantity: parseNumber(fullMatch[1]),
-      unit: 'st',
-      rawName: fullMatch[2] + ' ' + fullMatch[3],
-      note,
-    };
   }
 
   // Försök matcha "kvantitet namn" utan enhet — t.ex. "3 ägg"
-  const noUnitMatch = main.match(/^(\d+(?:[.,]\d+)?)\s+(.+)$/);
+  const noUnitMatch = main.match(QTY_NAME_RE);
   if (noUnitMatch) {
-    return {
+    return { quantity: parseNumber(noUnitMatch[1]), unit: 'st', rawName: noUnitMatch[2].trim(), note };
-      quantity: parseNumber(noUnitMatch[1]),
-      unit: 'st',
-      rawName: noUnitMatch[2].trim(),
-      note,
-    };
   }
 
   // Bara ett namn, ingen kvantitet — t.ex. "salt"
-  return {
+  return { quantity: 0, unit: '', rawName: main, note };
-    quantity: 0,
-    unit: '',
-    rawName: main,
-    note,
-  };
 }
 
 function parseNumber(s: string): number {