LibJS: Allow specifying keyword values not directly defined for a locale

For example, consider the locales "en-u-nu-fullwide" or "en-u-nu-arab".
The CLDR only declares the "latn" numbering system for the "en" locale,
thus ResolveLocale would change the locale to "en-u-nu-latn". This patch
allows using non-latn numbering systems digits.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2022, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -425,13 +425,15 @@ LocaleResult resolve_locale(Vector<String> const& requested_locales, LocaleOptio
         // b. Assert: Type(foundLocaleData) is Record.
         // c. Let keyLocaleData be foundLocaleData.[[<key>]].
         // d. Assert: Type(keyLocaleData) is List.
-        auto key_locale_data = Unicode::get_keywords_for_locale(found_locale, key);
+        auto key_locale_data = Unicode::get_available_keyword_values(key);
 
         // e. Let value be keyLocaleData[0].
         // f. Assert: Type(value) is either String or Null.
+        // NOTE: ECMA-402 assumes keyLocaleData is sorted by locale preference. Our list is sorted
+        //       alphabetically, so we get the locale's preferred value from LibUnicode.
         Optional<String> value;
-        if (!key_locale_data.is_empty())
+        if (auto preference = Unicode::get_preferred_keyword_value_for_locale(found_locale, key); preference.has_value())
-            value = key_locale_data[0];
+            value = *preference;
 
         // g. Let supportedExtensionAddition be "".
         Optional<Unicode::Keyword> supported_extension_addition {};

Userland/Libraries/LibJS/Tests/builtins/Intl/DateTimeFormat/DateTimeFormat.prototype.resolvedOptions.js

@@ -64,12 +64,12 @@ describe("correct behavior", () => {
     });
 
     test("numberingSystem option limited to known 'nu' values", () => {
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = Intl.DateTimeFormat("en", { numberingSystem: numberingSystem });
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });
 
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = Intl.DateTimeFormat(`en-u-nu-${numberingSystem}`);
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });

Userland/Libraries/LibJS/Tests/builtins/Intl/DurationFormat/DurationFormat.prototype.resolvedOptions.js

@@ -33,12 +33,12 @@ describe("correct behavior", () => {
     });
 
     test("numberingSystem option limited to known 'nu' values", () => {
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = new Intl.DurationFormat("en", { numberingSystem: numberingSystem });
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });
 
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = new Intl.DurationFormat(`en-u-nu-${numberingSystem}`);
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });

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

@@ -207,6 +207,21 @@ describe("style=decimal", () => {
         expect(en.format(12000000)).toBe("12 million");
         expect(en.format(12900000)).toBe("13 million");
 
+        const enFullwide = new Intl.NumberFormat("en", {
+            notation: "compact",
+            compactDisplay: "long",
+            numberingSystem: "fullwide",
+        });
+        expect(enFullwide.format(1)).toBe("１");
+        expect(enFullwide.format(1200)).toBe("１.２ thousand");
+        expect(enFullwide.format(1290)).toBe("１.３ thousand");
+        expect(enFullwide.format(12000)).toBe("１２ thousand");
+        expect(enFullwide.format(12900)).toBe("１３ thousand");
+        expect(enFullwide.format(1200000)).toBe("１.２ million");
+        expect(enFullwide.format(1290000)).toBe("１.３ million");
+        expect(enFullwide.format(12000000)).toBe("１２ million");
+        expect(enFullwide.format(12900000)).toBe("１３ million");
+
         const ar = new Intl.NumberFormat("ar", { notation: "compact", compactDisplay: "long" });
         expect(ar.format(1)).toBe("\u0661");
         expect(ar.format(1200)).toBe("\u0661\u066b\u0662 ألف");
@@ -579,6 +594,19 @@ describe("style=percent", () => {
         expect(en.format(0.123)).toBe("12%");
         expect(en.format(0.1234)).toBe("12%");
 
+        const enFullwide = new Intl.NumberFormat("en", {
+            style: "percent",
+            notation: "compact",
+            numberingSystem: "fullwide",
+        });
+        expect(enFullwide.format(0.01)).toBe("１%");
+        expect(enFullwide.format(0.012)).toBe("１.２%");
+        expect(enFullwide.format(0.0123)).toBe("１.２%");
+        expect(enFullwide.format(0.0129)).toBe("１.３%");
+        expect(enFullwide.format(0.12)).toBe("１２%");
+        expect(enFullwide.format(0.123)).toBe("１２%");
+        expect(enFullwide.format(0.1234)).toBe("１２%");
+
         const ar = new Intl.NumberFormat("ar", { style: "percent", notation: "compact" });
         expect(ar.format(0.01)).toBe("\u0661\u066a\u061c");
         expect(ar.format(0.012)).toBe("\u0661\u066b\u0662\u066a\u061c");

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

@@ -36,12 +36,12 @@ describe("correct behavior", () => {
     });
 
     test("numberingSystem option limited to known 'nu' values", () => {
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = Intl.NumberFormat("en", { numberingSystem: numberingSystem });
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });
 
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = Intl.NumberFormat(`en-u-nu-${numberingSystem}`);
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });

Userland/Libraries/LibJS/Tests/builtins/Intl/RelativeTimeFormat/RelativeTimeFormat.prototype.resolvedOptions.js

@@ -36,12 +36,12 @@ describe("correct behavior", () => {
     });
 
     test("numberingSystem option limited to known 'nu' values", () => {
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = new Intl.RelativeTimeFormat("en", { numberingSystem: numberingSystem });
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });
 
-        ["latn", "arab"].forEach(numberingSystem => {
+        ["latn", "foo"].forEach(numberingSystem => {
             const en = new Intl.RelativeTimeFormat(`en-u-nu-${numberingSystem}`);
             expect(en.resolvedOptions().numberingSystem).toBe("latn");
         });