Use client_secret : server side

[krabouilleur]

What Version of the library are you using?
17.0.0

Question
On my Angular website, I want to make authentication with gitlab auth module.
When I use the library, the lib use the /authorize (OK)
then I'm redirected to Gitlab where I have to authorize my application,
then I'm redirected to my website,
then the lib make the POST /token => but the /token must not be called directly by frontend but by bakcned (which will add the client_secret)

how tells the library to call the backend instead of gitlab ?