LibJS: Implement Uint8Array.prototype.toBase64

Userland/Libraries/LibJS/Runtime/Uint8Array.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Forward.h>
+#include <LibJS/Heap/GCPtr.h>
+
+namespace JS {
+
+class Uint8ArrayPrototypeHelpers {
+public:
+    static void initialize(Realm&, Object& prototype);
+
+private:
+    JS_DECLARE_NATIVE_FUNCTION(to_base64);
+};
+
+enum class Alphabet {
+    Base64,
+    Base64URL,
+};
+
+ThrowCompletionOr<NonnullGCPtr<TypedArrayBase>> validate_uint8_array(VM&);
+ThrowCompletionOr<ByteBuffer> get_uint8_array_bytes(VM&, TypedArrayBase const&);
+
+}