I make a post request to a server which responds with two headers that are important for the client: username and access-token.
The Network Tab of the Chrome debug tool disp
The front end will not be able to access that header unless the back end allows it.
In order to do so, you need to send a Access-Control-Expose-Headers header from the backend, and the value should be a comma separated list of the values you want to expose, i.e. access-token, username