feat(ext/fetch): add Headers#getSetCookie (#13542)

Spec change: https://github.com/whatwg/fetch/pull/1346
Tests: https://github.com/web-platform-tests/wpt/pull/31442 (ran against
this PR and they all pass)

---------

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/ext/fetch/20_headers.js b/ext/fetch/20_headers.js
index abf7433a3..bea542c30 100644
--- a/ext/fetch/20_headers.js
+++ b/ext/fetch/20_headers.js
@@ -308,6 +308,7 @@ class Headers {
    * @param {string} name
    */
   delete(name) {
+    webidl.assertBranded(this, HeadersPrototype);
     const prefix = "Failed to execute 'delete' on 'Headers'";
     webidl.requiredArguments(arguments.length, 1, prefix);
     name = webidl.converters["ByteString"](name, prefix, "Argument 1");
@@ -333,6 +334,7 @@ class Headers {
    * @param {string} name
    */
   get(name) {
+    webidl.assertBranded(this, HeadersPrototype);
     const prefix = "Failed to execute 'get' on 'Headers'";
     webidl.requiredArguments(arguments.length, 1, prefix);
     name = webidl.converters["ByteString"](name, prefix, "Argument 1");
@@ -345,10 +347,25 @@ class Headers {
     return getHeader(list, name);
   }
 
+  getSetCookie() {
+    webidl.assertBranded(this, HeadersPrototype);
+    const list = this[_headerList];
+
+    const entries = [];
+    for (let i = 0; i < list.length; i++) {
+      if (byteLowerCase(list[i][0]) === "set-cookie") {
+        ArrayPrototypePush(entries, list[i][1]);
+      }
+    }
+
+    return entries;
+  }
+
   /**
    * @param {string} name
    */
   has(name) {
+    webidl.assertBranded(this, HeadersPrototype);
     const prefix = "Failed to execute 'has' on 'Headers'";
     webidl.requiredArguments(arguments.length, 1, prefix);
     name = webidl.converters["ByteString"](name, prefix, "Argument 1");