LibJS: Add the TypedArray.of() method

Userland/Libraries/LibJS/Runtime/ErrorTypes.h

@@ -156,6 +156,7 @@
     M(TypedArrayInvalidByteOffset, "Invalid byte offset for {}: must be a multiple of {}, got {}")                                      \
     M(TypedArrayOutOfRangeByteOffset, "Typed array byte offset {} is out of range for buffer with length {}")                           \
     M(TypedArrayOutOfRangeByteOffsetOrLength, "Typed array range {}:{} is out of range for buffer with length {}")                      \
+    M(TypedArrayFailedSettingIndex, "Failed setting value of index {} of typed array")                                                  \
     M(UnknownIdentifier, "'{}' is not defined")                                                                                         \
     M(URIMalformed, "URI malformed")                                                                                                    \
     /* LibWeb bindings */                                                                                                               \

Userland/Libraries/LibJS/Runtime/TypedArrayConstructor.cpp

@@ -5,6 +5,7 @@
  */
 
 #include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/TypedArray.h>
 #include <LibJS/Runtime/TypedArrayConstructor.h>
 
 namespace JS {
@@ -26,6 +27,9 @@ void TypedArrayConstructor::initialize(GlobalObject& global_object)
     define_property(vm.names.prototype, global_object.typed_array_prototype(), 0);
     define_property(vm.names.length, Value(0), Attribute::Configurable);
 
+    u8 attr = Attribute::Writable | Attribute::Configurable;
+    define_native_function(vm.names.of, of, 0, attr);
+
     define_native_accessor(vm.well_known_symbol_species(), symbol_species_getter, {}, Attribute::Configurable);
 }
 
@@ -44,6 +48,60 @@ Value TypedArrayConstructor::construct(Function&)
     return {};
 }
 
+// 23.2.4.2 TypedArrayCreate ( constructor, argumentList ), https://tc39.es/ecma262/#typedarray-create
+static TypedArrayBase* typed_array_create(GlobalObject& global_object, Function& constructor, MarkedValueList arguments)
+{
+    auto& vm = global_object.vm();
+
+    auto argument_count = arguments.size();
+    auto first_argument = argument_count > 0 ? arguments[0] : js_undefined();
+
+    auto new_typed_array = vm.construct(constructor, constructor, move(arguments));
+    if (vm.exception())
+        return nullptr;
+    if (!new_typed_array.is_object() || !new_typed_array.as_object().is_typed_array()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::NotA, "TypedArray");
+        return nullptr;
+    }
+    auto& typed_array = static_cast<TypedArrayBase&>(new_typed_array.as_object());
+    if (typed_array.viewed_array_buffer()->is_detached()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::DetachedArrayBuffer);
+        return nullptr;
+    }
+    if (argument_count == 1 && first_argument.is_number() && typed_array.array_length() < first_argument.as_double()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::InvalidLength, "typed array");
+        return nullptr;
+    }
+    return &typed_array;
+}
+
+// 23.2.2.2 %TypedArray%.of ( ...items ), https://tc39.es/ecma262/#sec-%typedarray%.of
+JS_DEFINE_NATIVE_FUNCTION(TypedArrayConstructor::of)
+{
+    auto length = vm.argument_count();
+    auto constructor = vm.this_value(global_object);
+    if (!constructor.is_constructor()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::NotAConstructor, constructor.to_string_without_side_effects());
+        return {};
+    }
+    MarkedValueList arguments(vm.heap());
+    arguments.append(Value(length));
+    auto new_object = typed_array_create(global_object, constructor.as_function(), move(arguments));
+    if (vm.exception())
+        return {};
+    for (size_t k = 0; k < length; ++k) {
+        auto success = new_object->put(k, vm.argument(k));
+        if (vm.exception())
+            return {};
+        if (!success) {
+            vm.throw_exception<TypeError>(global_object, ErrorType::TypedArrayFailedSettingIndex, k);
+            return {};
+        }
+    }
+    return new_object;
+}
+
+// 23.2.2.4 get %TypedArray% [ @@species ], https://tc39.es/ecma262/#sec-get-%typedarray%-@@species
 JS_DEFINE_NATIVE_GETTER(TypedArrayConstructor::symbol_species_getter)
 {
     return vm.this_value(global_object);

Userland/Libraries/LibJS/Runtime/TypedArrayConstructor.h

@@ -25,6 +25,7 @@ public:
 private:
     virtual bool has_constructor() const override { return true; }
 
+    JS_DECLARE_NATIVE_FUNCTION(of);
     JS_DECLARE_NATIVE_GETTER(symbol_species_getter);
 };
 

Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.of.js

@@ -0,0 +1,28 @@
+const TYPED_ARRAYS = [
+    Uint8Array,
+    Uint16Array,
+    Uint32Array,
+    Int8Array,
+    Int16Array,
+    Int32Array,
+    Float32Array,
+    Float64Array,
+];
+
+const BIGINT_TYPED_ARRAYS = [BigUint64Array, BigInt64Array];
+
+test("basic functionality", () => {
+    TYPED_ARRAYS.forEach(T => {
+        const newTypedArray = T.of(1, 2, 3);
+        expect(newTypedArray[0]).toBe(1);
+        expect(newTypedArray[1]).toBe(2);
+        expect(newTypedArray[2]).toBe(3);
+    });
+
+    BIGINT_TYPED_ARRAYS.forEach(T => {
+        const newTypedArray = T.of(1n, 2n, 3n);
+        expect(newTypedArray[0]).toBe(1n);
+        expect(newTypedArray[1]).toBe(2n);
+        expect(newTypedArray[2]).toBe(3n);
+    });
+});