LibJS: Implement Intl.NumberFormat V3's [[SignDisplay]] changes

Intl.NumberFormat V3 adds a "negative" option for [[SignDisplay]] to
only use the locale's signed pattern for negative numbers.

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

@@ -1139,6 +1139,7 @@ RawFormatResult to_raw_fixed(GlobalObject& global_object, Value number, int min_
 }
 
 // 15.5.11 GetNumberFormatPattern ( numberFormat, x ), https://tc39.es/ecma402/#sec-getnumberformatpattern
+// 1.1.14 GetNumberFormatPattern ( numberFormat, x ), https://tc39.es/proposal-intl-numberformat-v3/out/numberformat/proposed.html#sec-getnumberformatpattern
 Optional<Variant<StringView, String>> get_number_format_pattern(GlobalObject& global_object, NumberFormat& number_format, Value number, Unicode::NumberFormat& found_pattern)
 {
     // 1. Let localeData be %NumberFormat%.[[LocaleData]].
@@ -1264,20 +1265,34 @@ Optional<Variant<StringView, String>> get_number_format_pattern(GlobalObject& gl
         }
         break;
 
-    // 15. Else,
+    // 15. Else if signDisplay is "exceptZero", then
     case NumberFormat::SignDisplay::ExceptZero:
-        // a. Assert: signDisplay is "exceptZero".
-        // b. If x is NaN, or if x is finite and ℝ(x) is 0, then
+        // a. If x is NaN, or if x is finite and ℝ(x) is 0, then
         if (is_positive_zero || is_negative_zero || is_nan) {
             // i. Let pattern be patterns.[[zeroPattern]].
             pattern = patterns->zero_format;
         }
-        // c. Else if ℝ(x) > 0, then
+        // b. Else if ℝ(x) > 0, then
         else if (is_greater_than(number, 0)) {
             // i. Let pattern be patterns.[[positivePattern]].
             pattern = patterns->positive_format;
         }
-        // d. Else,
+        // c. Else,
+        else {
+            // i. Let pattern be patterns.[[negativePattern]].
+            pattern = patterns->negative_format;
+        }
+        break;
+
+    // 16. Else,
+    case NumberFormat::SignDisplay::Negative:
+        // a. Assert: signDisplay is "negative".
+        // b. If x is 0 or x is -0 or x > 0 or x is NaN, then
+        if (is_positive_zero || is_negative_zero || is_greater_than(number, 0) || is_nan) {
+            // i. Let pattern be patterns.[[zeroPattern]].
+            pattern = patterns->zero_format;
+        }
+        // c. Else,
         else {
             // i. Let pattern be patterns.[[negativePattern]].
             pattern = patterns->negative_format;
@@ -1285,8 +1300,7 @@ Optional<Variant<StringView, String>> get_number_format_pattern(GlobalObject& gl
         break;
 
     default:
-        // FIXME: Handle all NumberFormat V3 [[SignDisplay]] options.
-        return {};
+        VERIFY_NOT_REACHED();
     }
 
     found_pattern = patterns.release_value();

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

@@ -347,6 +347,20 @@ describe("style=decimal", () => {
         expect(ar.format(-1)).toBe("\u061c-\u0661");
     });
 
+    test("signDisplay=negative", () => {
+        const en = new Intl.NumberFormat("en", { signDisplay: "negative" });
+        expect(en.format(0)).toBe("0");
+        expect(en.format(1)).toBe("1");
+        expect(en.format(-0)).toBe("0");
+        expect(en.format(-1)).toBe("-1");
+
+        const ar = new Intl.NumberFormat("ar", { signDisplay: "negative" });
+        expect(ar.format(0)).toBe("\u0660");
+        expect(ar.format(1)).toBe("\u0661");
+        expect(ar.format(-0)).toBe("\u0660");
+        expect(ar.format(-1)).toBe("\u061c-\u0661");
+    });
+
     test("useGrouping=always", () => {
         const en = new Intl.NumberFormat("en", { useGrouping: "always" });
         expect(en.format(123)).toBe("123");
@@ -626,6 +640,20 @@ describe("style=percent", () => {
         expect(ar.format(-0.0)).toBe("\u0660\u066a\u061c");
         expect(ar.format(-0.01)).toBe("\u061c-\u0661\u066a\u061c");
     });
+
+    test("signDisplay=negative", () => {
+        const en = new Intl.NumberFormat("en", { style: "percent", signDisplay: "negative" });
+        expect(en.format(0.0)).toBe("0%");
+        expect(en.format(0.01)).toBe("1%");
+        expect(en.format(-0.0)).toBe("0%");
+        expect(en.format(-0.01)).toBe("-1%");
+
+        const ar = new Intl.NumberFormat("ar", { style: "percent", signDisplay: "negative" });
+        expect(ar.format(0.0)).toBe("\u0660\u066a\u061c");
+        expect(ar.format(0.01)).toBe("\u0661\u066a\u061c");
+        expect(ar.format(-0.0)).toBe("\u0660\u066a\u061c");
+        expect(ar.format(-0.01)).toBe("\u061c-\u0661\u066a\u061c");
+    });
 });
 
 describe("style=currency", () => {
@@ -952,6 +980,50 @@ describe("style=currency", () => {
         expect(ar2.format(-0)).toBe("\u0660\u066b\u0660\u0660\u00a0US$");
         expect(ar2.format(-1)).toBe("\u061c-\u0661\u066b\u0660\u0660\u00a0US$");
     });
+
+    test("signDisplay=negative", () => {
+        const en1 = new Intl.NumberFormat("en", {
+            style: "currency",
+            currency: "USD",
+            signDisplay: "negative",
+        });
+        expect(en1.format(0)).toBe("$0.00");
+        expect(en1.format(1)).toBe("$1.00");
+        expect(en1.format(-0)).toBe("$0.00");
+        expect(en1.format(-1)).toBe("-$1.00");
+
+        const en2 = new Intl.NumberFormat("en", {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "negative",
+        });
+        expect(en2.format(0)).toBe("$0.00");
+        expect(en2.format(1)).toBe("$1.00");
+        expect(en2.format(-0)).toBe("$0.00");
+        expect(en2.format(-1)).toBe("($1.00)");
+
+        const ar1 = new Intl.NumberFormat("ar", {
+            style: "currency",
+            currency: "USD",
+            signDisplay: "negative",
+        });
+        expect(ar1.format(0)).toBe("\u0660\u066b\u0660\u0660\u00a0US$");
+        expect(ar1.format(1)).toBe("\u0661\u066b\u0660\u0660\u00a0US$");
+        expect(ar1.format(-0)).toBe("\u0660\u066b\u0660\u0660\u00a0US$");
+        expect(ar1.format(-1)).toBe("\u061c-\u0661\u066b\u0660\u0660\u00a0US$");
+
+        const ar2 = new Intl.NumberFormat("ar", {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "negative",
+        });
+        expect(ar2.format(0)).toBe("\u0660\u066b\u0660\u0660\u00a0US$");
+        expect(ar2.format(1)).toBe("\u0661\u066b\u0660\u0660\u00a0US$");
+        expect(ar2.format(-0)).toBe("\u0660\u066b\u0660\u0660\u00a0US$");
+        expect(ar2.format(-1)).toBe("\u061c-\u0661\u066b\u0660\u0660\u00a0US$");
+    });
 });
 
 describe("style=unit", () => {

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

@@ -171,6 +171,26 @@ describe("style=decimal", () => {
         ]);
     });
 
+    test("signDisplay=negative", () => {
+        const en = new Intl.NumberFormat("en", { signDisplay: "negative" });
+        expect(en.formatToParts(0)).toEqual([{ type: "integer", value: "0" }]);
+        expect(en.formatToParts(1)).toEqual([{ type: "integer", value: "1" }]);
+        expect(en.formatToParts(-0)).toEqual([{ type: "integer", value: "0" }]);
+        expect(en.formatToParts(-1)).toEqual([
+            { type: "minusSign", value: "-" },
+            { type: "integer", value: "1" },
+        ]);
+
+        const ar = new Intl.NumberFormat("ar", { signDisplay: "negative" });
+        expect(ar.formatToParts(0)).toEqual([{ type: "integer", value: "\u0660" }]);
+        expect(ar.formatToParts(1)).toEqual([{ type: "integer", value: "\u0661" }]);
+        expect(ar.formatToParts(-0)).toEqual([{ type: "integer", value: "\u0660" }]);
+        expect(ar.formatToParts(-1)).toEqual([
+            { type: "minusSign", value: "\u061c-" },
+            { type: "integer", value: "\u0661" },
+        ]);
+    });
+
     test("useGrouping=always", () => {
         const en = new Intl.NumberFormat("en", { useGrouping: "always" });
         expect(en.formatToParts(1234)).toEqual([
@@ -588,6 +608,46 @@ describe("style=percent", () => {
             { type: "percentSign", value: "\u066a\u061c" },
         ]);
     });
+
+    test("signDisplay=negative", () => {
+        const en = new Intl.NumberFormat("en", { style: "percent", signDisplay: "negative" });
+        expect(en.formatToParts(0.0)).toEqual([
+            { type: "integer", value: "0" },
+            { type: "percentSign", value: "%" },
+        ]);
+        expect(en.formatToParts(0.01)).toEqual([
+            { type: "integer", value: "1" },
+            { type: "percentSign", value: "%" },
+        ]);
+        expect(en.formatToParts(-0.0)).toEqual([
+            { type: "integer", value: "0" },
+            { type: "percentSign", value: "%" },
+        ]);
+        expect(en.formatToParts(-0.01)).toEqual([
+            { type: "minusSign", value: "-" },
+            { type: "integer", value: "1" },
+            { type: "percentSign", value: "%" },
+        ]);
+
+        const ar = new Intl.NumberFormat("ar", { style: "percent", signDisplay: "negative" });
+        expect(ar.formatToParts(0.0)).toEqual([
+            { type: "integer", value: "\u0660" },
+            { type: "percentSign", value: "\u066a\u061c" },
+        ]);
+        expect(ar.formatToParts(0.01)).toEqual([
+            { type: "integer", value: "\u0661" },
+            { type: "percentSign", value: "\u066a\u061c" },
+        ]);
+        expect(ar.formatToParts(-0.0)).toEqual([
+            { type: "integer", value: "\u0660" },
+            { type: "percentSign", value: "\u066a\u061c" },
+        ]);
+        expect(ar.formatToParts(-0.01)).toEqual([
+            { type: "minusSign", value: "\u061c-" },
+            { type: "integer", value: "\u0661" },
+            { type: "percentSign", value: "\u066a\u061c" },
+        ]);
+    });
 });
 
 describe("style=currency", () => {
@@ -1133,6 +1193,107 @@ describe("style=currency", () => {
             { type: "literal", value: ")" },
         ]);
     });
+
+    test("signDisplay=negative", () => {
+        const en = new Intl.NumberFormat("en", {
+            style: "currency",
+            currency: "USD",
+            signDisplay: "negative",
+        });
+        expect(en.formatToParts(0)).toEqual([
+            { type: "currency", value: "$" },
+            { type: "integer", value: "0" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "00" },
+        ]);
+        expect(en.formatToParts(1)).toEqual([
+            { type: "currency", value: "$" },
+            { type: "integer", value: "1" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "00" },
+        ]);
+        expect(en.formatToParts(-0)).toEqual([
+            { type: "currency", value: "$" },
+            { type: "integer", value: "0" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "00" },
+        ]);
+        expect(en.formatToParts(-1)).toEqual([
+            { type: "minusSign", value: "-" },
+            { type: "currency", value: "$" },
+            { type: "integer", value: "1" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "00" },
+        ]);
+
+        const ar = new Intl.NumberFormat("ar", {
+            style: "currency",
+            currency: "USD",
+            signDisplay: "negative",
+        });
+        expect(ar.formatToParts(0)).toEqual([
+            { type: "integer", value: "\u0660" },
+            { type: "decimal", value: "\u066b" },
+            { type: "fraction", value: "\u0660\u0660" },
+            { type: "literal", value: "\u00a0" },
+            { type: "currency", value: "US$" },
+        ]);
+        expect(ar.formatToParts(1)).toEqual([
+            { type: "integer", value: "\u0661" },
+            { type: "decimal", value: "\u066b" },
+            { type: "fraction", value: "\u0660\u0660" },
+            { type: "literal", value: "\u00a0" },
+            { type: "currency", value: "US$" },
+        ]);
+        expect(ar.formatToParts(-0)).toEqual([
+            { type: "integer", value: "\u0660" },
+            { type: "decimal", value: "\u066b" },
+            { type: "fraction", value: "\u0660\u0660" },
+            { type: "literal", value: "\u00a0" },
+            { type: "currency", value: "US$" },
+        ]);
+        expect(ar.formatToParts(-1)).toEqual([
+            { type: "minusSign", value: "\u061c-" },
+            { type: "integer", value: "\u0661" },
+            { type: "decimal", value: "\u066b" },
+            { type: "fraction", value: "\u0660\u0660" },
+            { type: "literal", value: "\u00a0" },
+            { type: "currency", value: "US$" },
+        ]);
+
+        const zh = new Intl.NumberFormat("zh-Hant-u-nu-hanidec", {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "negative",
+        });
+        expect(zh.formatToParts(0)).toEqual([
+            { type: "currency", value: "US$" },
+            { type: "integer", value: "〇" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "〇〇" },
+        ]);
+        expect(zh.formatToParts(1)).toEqual([
+            { type: "currency", value: "US$" },
+            { type: "integer", value: "一" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "〇〇" },
+        ]);
+        expect(zh.formatToParts(-0)).toEqual([
+            { type: "currency", value: "US$" },
+            { type: "integer", value: "〇" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "〇〇" },
+        ]);
+        expect(zh.formatToParts(-1)).toEqual([
+            { type: "literal", value: "(" },
+            { type: "currency", value: "US$" },
+            { type: "integer", value: "一" },
+            { type: "decimal", value: "." },
+            { type: "fraction", value: "〇〇" },
+            { type: "literal", value: ")" },
+        ]);
+    });
 });
 
 describe("style=unit", () => {