fix: Show minimum value for quantity (#7077)

frontend/composables/recipes/use-recipe-ingredients.test.ts

@@ -205,4 +205,34 @@ describe("parseIngredientText", () => {
 
     expect(parseIngredientText(ingredient)).toEqual("2 tablespoons diced onion");
   });
+
+  test("decimal below minimum precision shows < 0.001", () => {
+    const ingredient = createRecipeIngredient({
+      quantity: 0.0001,
+      unit: { id: "1", name: "cup", useAbbreviation: false },
+      food: { id: "1", name: "salt" },
+    });
+
+    expect(parseIngredientText(ingredient)).toEqual("&lt; 0.001 cup salt");
+  });
+
+  test("fraction below minimum denominator shows < 1/10", () => {
+    const ingredient = createRecipeIngredient({
+      quantity: 0.05,
+      unit: { id: "1", name: "cup", fraction: true, useAbbreviation: false },
+      food: { id: "1", name: "salt" },
+    });
+
+    expect(parseIngredientText(ingredient)).toEqual("&lt; <sup>1</sup><span>⁄</span><sub>10</sub> cup salt");
+  });
+
+  test("fraction below minimum denominator without formatting shows < 1/10", () => {
+    const ingredient = createRecipeIngredient({
+      quantity: 0.05,
+      unit: { id: "1", name: "cup", fraction: true, useAbbreviation: false },
+      food: { id: "1", name: "salt" },
+    });
+
+    expect(parseIngredientText(ingredient, 1, false)).toEqual("&lt; 1/10 cup salt");
+  });
 });

frontend/composables/recipes/use-recipe-ingredients.ts

@@ -5,6 +5,9 @@ import type { CreateIngredientFood, CreateIngredientUnit, IngredientFood, Ingred
 
 const { frac } = useFraction();
 
+const FRAC_MIN_DENOM = 10;
+const DECIMAL_PRECISION = 3;
+
 export function sanitizeIngredientHTML(rawHtml: string) {
   return DOMPurify.sanitize(rawHtml, {
     USE_PROFILES: { html: true },
@@ -91,11 +94,19 @@ export function useIngredientTextParser() {
 
     // casting to number is required as sometimes quantity is a string
     if (quantity && Number(quantity) !== 0) {
+      const scaledQuantity = Number((quantity * scale));
+
       if (unit && !unit.fraction) {
-        returnQty = Number((quantity * scale).toPrecision(3)).toString();
+        const minVal = 10 ** -DECIMAL_PRECISION;
+        returnQty = scaledQuantity >= minVal
+          ? Number(scaledQuantity.toPrecision(DECIMAL_PRECISION)).toString()
+          : `< ${minVal}`;
       }
       else {
-        const fraction = frac(quantity * scale, 10, true);
+        const minVal = 1 / FRAC_MIN_DENOM;
+        const isUnderMinVal = !(scaledQuantity >= minVal);
+
+        const fraction = !isUnderMinVal ? frac(scaledQuantity, FRAC_MIN_DENOM, true) : [0, 1, FRAC_MIN_DENOM];
         if (fraction[0] !== undefined && fraction[0] > 0) {
           returnQty += fraction[0];
         }
@@ -105,6 +116,10 @@ export function useIngredientTextParser() {
             ? `<sup>${fraction[1]}</sup><span>&frasl;</span><sub>${fraction[2]}</sub>`
             : ` ${fraction[1]}/${fraction[2]}`;
         }
+
+        if (isUnderMinVal) {
+          returnQty = `< ${returnQty}`;
+        }
       }
     }