diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
index 2b3db2a6054..b1e9c8b3433 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
@@ -644,13 +644,28 @@ static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter
 )~~~");
         }
     } else if (parameter.type->name() == "BufferSource") {
+        if (optional) {
+            scoped_generator.append(R"~~~(
+    Optional<JS::Handle<JS::Object>> @cpp_name@;
+    if (!@js_name@@js_suffix@.is_undefined()) {
+)~~~");
+        } else {
+            scoped_generator.append(R"~~~(
+    JS::Handle<JS::Object> @cpp_name@;
+)~~~");
+        }
         scoped_generator.append(R"~~~(
     if (!@js_name@@js_suffix@.is_object() || !(is<JS::TypedArrayBase>(@js_name@@js_suffix@.as_object()) || is<JS::ArrayBuffer>(@js_name@@js_suffix@.as_object()) || is<JS::DataView>(@js_name@@js_suffix@.as_object())))
         return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "@parameter.type.name@");
 
     // TODO: Should we make this a Variant?
-    auto @cpp_name@ = JS::make_handle(&@js_name@@js_suffix@.as_object());
+    @cpp_name@ = JS::make_handle(&@js_name@@js_suffix@.as_object());
 )~~~");
+        if (optional) {
+            scoped_generator.append(R"~~~(
+        }
+)~~~");
+        }
     } else if (parameter.type->name() == "any") {
         if (variadic) {
             scoped_generator.append(R"~~~(
diff --git a/Tests/LibWeb/Text/expected/TextDecoder/TextDecoder_decode.txt b/Tests/LibWeb/Text/expected/TextDecoder/TextDecoder_decode.txt
new file mode 100644
index 00000000000..8fc16ea51f2
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/TextDecoder/TextDecoder_decode.txt
@@ -0,0 +1,2 @@
+[ABC]
+[]
diff --git a/Tests/LibWeb/Text/input/TextDecoder/TextDecoder_decode.html b/Tests/LibWeb/Text/input/TextDecoder/TextDecoder_decode.html
new file mode 100644
index 00000000000..4a2273770ce
--- /dev/null
+++ b/Tests/LibWeb/Text/input/TextDecoder/TextDecoder_decode.html
@@ -0,0 +1,12 @@
+<script src="../include.js"></script>
+<script>
+    test(() => {
+        try {
+            let decoder = new TextDecoder("utf-8");
+            println(`[${decoder.decode(new Uint8Array([0x41, 0x42, 0x43]))}]`); // "ABC"
+            println(`[${decoder.decode()}]`);
+        } catch(e) {
+            println("ERROR: " + e.name + ": " + e.message);
+        }
+    });
+</script>
diff --git a/Userland/Libraries/LibWeb/Encoding/TextDecoder.cpp b/Userland/Libraries/LibWeb/Encoding/TextDecoder.cpp
index d975b7f8b58..eb02aa78221 100644
--- a/Userland/Libraries/LibWeb/Encoding/TextDecoder.cpp
+++ b/Userland/Libraries/LibWeb/Encoding/TextDecoder.cpp
@@ -44,11 +44,14 @@ JS::ThrowCompletionOr<void> TextDecoder::initialize(JS::Realm& realm)
 }
 
 // https://encoding.spec.whatwg.org/#dom-textdecoder-decode
-WebIDL::ExceptionOr<DeprecatedString> TextDecoder::decode(JS::Handle<JS::Object> const& input) const
+WebIDL::ExceptionOr<DeprecatedString> TextDecoder::decode(Optional<JS::Handle<JS::Object>> const& input) const
 {
+    if (!input.has_value())
+        return TRY_OR_THROW_OOM(vm(), m_decoder.to_utf8({}));
+
     // FIXME: Implement the streaming stuff.
 
-    auto data_buffer_or_error = WebIDL::get_buffer_source_copy(*input.cell());
+    auto data_buffer_or_error = WebIDL::get_buffer_source_copy(*input->cell());
     if (data_buffer_or_error.is_error())
         return WebIDL::OperationError::create(realm(), "Failed to copy bytes from ArrayBuffer");
     auto& data_buffer = data_buffer_or_error.value();
diff --git a/Userland/Libraries/LibWeb/Encoding/TextDecoder.h b/Userland/Libraries/LibWeb/Encoding/TextDecoder.h
index 02210830ae7..e5e7c72f9ba 100644
--- a/Userland/Libraries/LibWeb/Encoding/TextDecoder.h
+++ b/Userland/Libraries/LibWeb/Encoding/TextDecoder.h
@@ -25,7 +25,7 @@ public:
 
     virtual ~TextDecoder() override;
 
-    WebIDL::ExceptionOr<DeprecatedString> decode(JS::Handle<JS::Object> const&) const;
+    WebIDL::ExceptionOr<DeprecatedString> decode(Optional<JS::Handle<JS::Object>> const&) const;
 
     DeprecatedFlyString const& encoding() const { return m_encoding; }
     bool fatal() const { return m_fatal; }