Refresh token JS

Ok I read over the links you gave me Barry (thank you btw) and I tried setting up the call in different ways but am still getting a failure. I read the ajax post stuff but not exactly sure how that setup should look. I talked to my prof and he was less than helpful basically saying go Google it.

So here is what I got so far (and yes I know the whole key, secret thing but this is for a class project, its fine, I am not concerned about that)

function refreshToken (storeToken, data)
{

    if(storeToken >= 120)
    {
        console.log("Token still valid for " , storeToken);
    }

    else{
        console.log("Token is or soon to be expired. Time remaining " , storeToken);

        return $.ajax({

            url : "https://id.twitch.tv/oauth2/token",
            type : "POST",
            data : {

                grant_type : "refresh_token",
                refresh_token : data.refresh_token,
                client_id : "HappyNewYear2019",
                client_secret : "ISwearIHateJSSometimes",
               
            },
            success : constants.successTag,
            error : () => {console.log("refresh failed ")},
            

        })
        
    }
    
}

I also am not too sure what response I am expecting to get back. Am I getting only a new access token or an access token and new refresh token? or the whole user object back?