LibWeb: Implement TextEncoder.prototype.encoding

Userland/Libraries/LibWeb/Encoding/TextEncoder.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/FlyString.h>
 #include <LibJS/Runtime/TypedArray.h>
 #include <LibWeb/Bindings/Wrapper.h>
 #include <LibWeb/Encoding/TextEncoder.h>
@@ -33,4 +34,11 @@ JS::Uint8Array* TextEncoder::encode(String const& input) const
     return typed_array;
 }
 
+// https://encoding.spec.whatwg.org/#dom-textencoder-encoding
+FlyString const& TextEncoder::encoding()
+{
+    static FlyString encoding = "utf-8"sv;
+    return encoding;
+}
+
 }

Userland/Libraries/LibWeb/Encoding/TextEncoder.h

@@ -34,6 +34,8 @@ public:
 
     JS::Uint8Array* encode(String const& input) const;
 
+    static FlyString const& encoding();
+
 protected:
     // https://encoding.spec.whatwg.org/#dom-textencoder
     TextEncoder() = default;

Userland/Libraries/LibWeb/Encoding/TextEncoder.idl

@@ -5,5 +5,5 @@ interface TextEncoder {
     [NewObject] Uint8Array encode(optional USVString input = "");
     // TextEncoderEncodeIntoResult encodeInto(USVString source, [AllowShared] Uint8Array destination);
 
-    // readonly attribute DOMString encoding;
+    readonly attribute DOMString encoding;
 };

Userland/Libraries/LibWeb/Tests/Encoding/TextEncoder.prototype.encoding.js

@@ -0,0 +1,12 @@
+describe("normal behavior", () => {
+    loadLocalPage("/res/html/misc/blank.html");
+
+    afterInitialPageLoad(page => {
+        test("Basic functionality", () => {
+            const textEncoder = new page.TextEncoder();
+
+            expect(textEncoder.encoding).toBe("utf-8");
+        });
+    });
+    waitForPageToLoad();
+});