refactor: store header keys lower case internally (#10958)

This is a minor optimization that removes some header key lowercasing
that previously happened on access.

1 files changed, 2 insertions, 4 deletions

diff --git a/extensions/fetch/23_request.js b/extensions/fetch/23_request.js
index 4d79d74be..ff2bf1d4e 100644
--- a/extensions/fetch/23_request.js
+++ b/extensions/fetch/23_request.js
@@ -152,10 +152,8 @@
       let charset = null;
       let essence = null;
       let mimeType = null;
-      const values = getDecodeSplitHeader(
-        headerListFromHeaders(this[_headers]),
-        "Content-Type",
-      );
+      const headerList = headerListFromHeaders(this[_headers]);
+      const values = getDecodeSplitHeader(headerList, "content-type");
       if (values === null) return null;
       for (const value of values) {
         const temporaryMimeType = mimesniff.parseMimeType(value);