LibJS: Respect per-locale minimum grouping digits when number formatting

Userland/Libraries/LibJS/Runtime/Intl/NumberFormat.cpp

@@ -714,27 +714,29 @@ Vector<PatternPartition> partition_number_pattern(NumberFormat& number_format, d
 static Vector<StringView> separate_integer_into_groups(Unicode::NumberGroupings const& grouping_sizes, StringView integer)
 {
     Utf8View utf8_integer { integer };
+    if (utf8_integer.length() <= grouping_sizes.primary_grouping_size)
+        return { integer };
+
+    size_t index = utf8_integer.length() - grouping_sizes.primary_grouping_size;
+    if (index < grouping_sizes.minimum_grouping_digits)
+        return { integer };
+
     Vector<StringView> groups;
 
     auto add_group = [&](size_t index, size_t length) {
         groups.prepend(utf8_integer.unicode_substring_view(index, length).as_string());
     };
 
-    if (utf8_integer.length() > grouping_sizes.primary_grouping_size) {
-        size_t index = utf8_integer.length() - grouping_sizes.primary_grouping_size;
-        add_group(index, grouping_sizes.primary_grouping_size);
+    add_group(index, grouping_sizes.primary_grouping_size);
 
-        while (index > grouping_sizes.secondary_grouping_size) {
-            index -= grouping_sizes.secondary_grouping_size;
-            add_group(index, grouping_sizes.secondary_grouping_size);
-        }
-
-        if (index > 0)
-            add_group(0, index);
-    } else {
-        groups.append(integer);
+    while (index > grouping_sizes.secondary_grouping_size) {
+        index -= grouping_sizes.secondary_grouping_size;
+        add_group(index, grouping_sizes.secondary_grouping_size);
     }
 
+    if (index > 0)
+        add_group(0, index);
+
     return groups;
 }
 

Userland/Libraries/LibJS/Tests/builtins/Intl/NumberFormat/NumberFormat.prototype.format.js

@@ -378,6 +378,13 @@ describe("style=decimal", () => {
         expect(ar.format(12345)).toBe("\u0661\u0662\u066c\u0663\u0664\u0665");
         expect(ar.format(123456)).toBe("\u0661\u0662\u0663\u066c\u0664\u0665\u0666");
         expect(ar.format(1234567)).toBe("\u0661\u066c\u0662\u0663\u0664\u066c\u0665\u0666\u0667");
+
+        const plPl = new Intl.NumberFormat("pl-PL", { useGrouping: true });
+        expect(plPl.format(123)).toBe("123");
+        expect(plPl.format(1234)).toBe("1234");
+        expect(plPl.format(12345)).toBe("12\u00a0345");
+        expect(plPl.format(123456)).toBe("123\u00a0456");
+        expect(plPl.format(1234567)).toBe("1\u00a0234\u00a0567");
     });
 
     test("useGrouping=false", () => {
@@ -401,6 +408,13 @@ describe("style=decimal", () => {
         expect(ar.format(12345)).toBe("\u0661\u0662\u0663\u0664\u0665");
         expect(ar.format(123456)).toBe("\u0661\u0662\u0663\u0664\u0665\u0666");
         expect(ar.format(1234567)).toBe("\u0661\u0662\u0663\u0664\u0665\u0666\u0667");
+
+        const plPl = new Intl.NumberFormat("pl-PL", { useGrouping: false });
+        expect(plPl.format(123)).toBe("123");
+        expect(plPl.format(1234)).toBe("1234");
+        expect(plPl.format(12345)).toBe("12345");
+        expect(plPl.format(123456)).toBe("123456");
+        expect(plPl.format(1234567)).toBe("1234567");
     });
 });