LibWeb: Implement TextEncoder.prototype.encode()

Userland/Libraries/LibWeb/Encoding/TextEncoder.cpp

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/TypedArray.h>
+#include <LibWeb/Bindings/Wrapper.h>
+#include <LibWeb/Encoding/TextEncoder.h>
+
+namespace Web::Encoding {
+
+// https://encoding.spec.whatwg.org/#dom-textencoder-encode
+JS::Uint8Array* TextEncoder::encode(String const& input) const
+{
+    auto& global_object = wrapper()->global_object();
+
+    // NOTE: The AK::String returned from PrimitiveString::string() is always UTF-8, regardless of the internal string type, so most of these steps are no-ops.
+
+    // 1. Convert input to an I/O queue of scalar values.
+    // 2. Let output be the I/O queue of bytes « end-of-queue ».
+    // 3. While true:
+    //     1. Let item be the result of reading from input.
+    //     2. Let result be the result of processing an item with item, an instance of the UTF-8 encoder, input, output, and "fatal".
+    //     3. Assert: result is not an error.
+    //     4. If result is finished, then convert output into a byte sequence and return a Uint8Array object wrapping an ArrayBuffer containing output.
+
+    auto byte_buffer = input.to_byte_buffer();
+
+    // FIXME: Support `TypedArray::create()` with existing `ArrayBuffer`, so that we don't have to allocate two `ByteBuffer`s.
+    auto* typed_array = JS::Uint8Array::create(global_object, byte_buffer.size());
+    typed_array->viewed_array_buffer()->buffer() = move(byte_buffer);
+    return typed_array;
+}
+
+}