1 files changed, 47 insertions, 3 deletions
diff --git a/Userland/Libraries/LibJS/Runtime/ArrayBufferConstructor.cpp b/Userland/Libraries/LibJS/Runtime/ArrayBufferConstructor.cpp
index 43318a0328..db1a394e66 100644
--- a/Userland/Libraries/LibJS/Runtime/ArrayBufferConstructor.cpp
+++ b/Userland/Libraries/LibJS/Runtime/ArrayBufferConstructor.cpp
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -46,20 +47,63 @@ ThrowCompletionOr<Value> ArrayBufferConstructor::call()
     return vm.throw_completion<TypeError>(global_object(), ErrorType::ConstructorWithoutNew, vm.names.ArrayBuffer);
 }
 
+// 1.1.6 GetArrayBufferMaxByteLengthOption ( options ), https://tc39.es/proposal-resizablearraybuffer/#sec-getarraybuffermaxbytelengthoption
+static ThrowCompletionOr<Optional<size_t>> get_array_buffer_max_byte_length_option(VM& vm, GlobalObject& global_object, Value options)
+{
+    // 1. If Type(options) is not Object, return empty.
+    if (!options.is_object())
+        return Optional<size_t>();
+
+    // 2. Let maxByteLength be ? Get(options, "maxByteLength").
+    auto max_byte_length = TRY(options.get(global_object, vm.names.maxByteLength));
+
+    // 3. If maxByteLength is undefined, return empty.
+    if (max_byte_length.is_undefined())
+        return Optional<size_t>();
+
+    // 4. Return ? ToIndex(maxByteLength).
+    return TRY(max_byte_length.to_index(global_object));
+}
+
 // 25.1.3.1 ArrayBuffer ( length ), https://tc39.es/ecma262/#sec-arraybuffer-length
+// 1.2.1 ArrayBuffer ( length [, options ] ), https://tc39.es/proposal-resizablearraybuffer/#sec-arraybuffer-constructor
 ThrowCompletionOr<Object*> ArrayBufferConstructor::construct(FunctionObject& new_target)
 {
+    auto& global_object = new_target.realm()->global_object();
     auto& vm = this->vm();
-    auto byte_length_or_error = vm.argument(0).to_index(global_object());
+
+    // 1. If NewTarget is undefined, throw a TypeError exception.
+    // NOTE: See `ArrayBufferConstructor::call()`
+
+    // 2. Let byteLength be ? ToIndex(length).
+    auto byte_length_or_error = vm.argument(0).to_index(global_object);
     if (byte_length_or_error.is_error()) {
         auto error = byte_length_or_error.release_error();
         if (error.value()->is_object() && is<RangeError>(error.value()->as_object())) {
             // Re-throw more specific RangeError
-            return vm.throw_completion<RangeError>(global_object(), ErrorType::InvalidLength, "array buffer");
+            return vm.throw_completion<RangeError>(global_object, ErrorType::InvalidLength, "array buffer");
         }
         return error;
     }
-    return TRY(allocate_array_buffer(global_object(), new_target, byte_length_or_error.release_value()));
+    auto byte_length = byte_length_or_error.release_value();
+
+    // 3. Let requestedMaxByteLength be ? GetArrayBufferMaxByteLengthOption(options).
+    auto options = vm.argument(1);
+    auto requested_max_byte_length_value = TRY(get_array_buffer_max_byte_length_option(vm, global_object, options));
+
+    // 4. If requestedMaxByteLength is empty, then
+    if (!requested_max_byte_length_value.has_value()) {
+        // a. Return ? AllocateArrayBuffer(NewTarget, byteLength).
+        return TRY(allocate_array_buffer(global_object, new_target, byte_length));
+    }
+    auto requested_max_byte_length = requested_max_byte_length_value.release_value();
+
+    // 5. If byteLength > requestedMaxByteLength, throw a RangeError exception.
+    if (byte_length > requested_max_byte_length)
+        return vm.throw_completion<RangeError>(global_object, ErrorType::ByteLengthBeyondRequestedMax);
+
+    // 6. Return ? AllocateArrayBuffer(NewTarget, byteLength, requestedMaxByteLength).
+    return TRY(allocate_array_buffer(global_object, new_target, byte_length, requested_max_byte_length));
 }
 
 // 25.1.4.1 ArrayBuffer.isView ( arg ), https://tc39.es/ecma262/#sec-arraybuffer.isview