LibJS: Add %TypedArray%.prototype.toLocaleString

Author: https://github.com/IdanHo
Commit: https://github.com/SerenityOS/serenity/commit/a44de7a55f0
Pull-request: https://github.com/SerenityOS/serenity/pull/8592
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp

@@ -53,6 +53,7 @@ void TypedArrayPrototype::initialize(GlobalObject& object)
     define_native_function(vm.names.copyWithin, copy_within, 2, attr);
     define_native_function(vm.names.filter, filter, 1, attr);
     define_native_function(vm.names.map, map, 1, attr);
+    define_native_function(vm.names.toLocaleString, to_locale_string, 0, attr);
 
     define_native_accessor(*vm.well_known_symbol_to_string_tag(), to_string_tag_getter, nullptr, Attribute::Configurable);
 
@@ -1452,4 +1453,36 @@ JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::map)
     return return_array;
 }
 
+// 23.2.3.28 %TypedArray%.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] ), https://tc39.es/ecma262/#sec-%typedarray%.prototype.tolocalestring
+JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::to_locale_string)
+{
+    auto* typed_array = validate_typed_array(global_object);
+    if (!typed_array)
+        return {};
+
+    auto length = typed_array->array_length();
+
+    StringBuilder builder;
+    for (u32 k = 0; k < length; ++k) {
+        if (k > 0)
+            builder.append(','); // NOTE: Until we implement ECMA-402 (Intl) this is implementation specific.
+        auto value = typed_array->get(k);
+        if (vm.exception())
+            return {};
+        if (value.is_nullish())
+            continue;
+        auto* value_object = value.to_object(global_object);
+        if (!value_object)
+            return {};
+        auto locale_string_result = value_object->invoke(vm.names.toLocaleString);
+        if (vm.exception())
+            return {};
+        auto string = locale_string_result.to_string(global_object);
+        if (vm.exception())
+            return {};
+        builder.append(string);
+    }
+    return js_string(vm, builder.to_string());
+}
+
 }

Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.h

@@ -49,6 +49,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(copy_within);
     JS_DECLARE_NATIVE_FUNCTION(filter);
     JS_DECLARE_NATIVE_FUNCTION(map);
+    JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
 };
 
 }

Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.prototype.toLocaleString.js

@@ -0,0 +1,37 @@
+const TYPED_ARRAYS = [
+    Uint8Array,
+    Uint8ClampedArray,
+    Uint16Array,
+    Uint32Array,
+    Int8Array,
+    Int16Array,
+    Int32Array,
+    Float32Array,
+    Float64Array,
+];
+
+const BIGINT_TYPED_ARRAYS = [BigUint64Array, BigInt64Array];
+
+test("basic functionality", () => {
+    TYPED_ARRAYS.forEach(T => {
+        expect(T.prototype.toLocaleString).toHaveLength(0);
+
+        const typedArray = new T(3);
+        typedArray[0] = 1;
+        typedArray[1] = 2;
+        typedArray[2] = 3;
+
+        expect(typedArray.toLocaleString()).toBe("1,2,3");
+    });
+
+    BIGINT_TYPED_ARRAYS.forEach(T => {
+        expect(T.prototype.toLocaleString).toLocaleString(0);
+
+        const typedArray = new T(3);
+        typedArray[0] = 1n;
+        typedArray[1] = 2n;
+        typedArray[2] = 3n;
+
+        expect(typedArray.toLocaleString()).toBe("1,2,3");
+    });
+});