Reading response headers with Fetch API

Question

I\'m in a Google Chrome extension with permissions for \"*://*/*\" and I\'m trying to make the switch from XMLHttpRequest to the Fetch API.

The extensio

Answer 1

There is a restriction to access response headers when you are using Fetch API over CORS. Due to this restriction, you can access only following standard headers:

• Cache-Control
• Content-Language
• Content-Type
• Expires
• Last-Modified
• Pragma

When you are writing code for Google Chrome extension, you are using CORS, hence you can't access all headers. If you control the server, you can return custom information in the response body instead of headers

More info on this restriction - https://developers.google.com/web/updates/2015/03/introduction-to-fetch#response_types