New endpoints and logic for the new flow

In server.js we need to add a new endpoint

app.post("/auth/auth-options", (req, res) => {
    const user = findUser(req.body.email);    

    if (user) {
        res.send({
            password: true,
            google: user.federated && user.federated.google,
            webauthn: user.webauthn
        })
    } else {
        res.send({
            password: true
        })
    }
});

Then on API.js

checkAuthOptions:  async (user) => {
    return await API.makePostRequest(API.endpoint + "auth-options", user);
},

And finally, on Auth.js we change login while adding a new checkAuthOptions method:

login: async (event) => {
    if (event) event.preventDefault();
    if (Auth.loginStep==1) {
        Auth.checkAuthOptions();
    } else {
        const user = {
            email: document.getElementById("login_email").value,
            password: document.getElementById("login_password").value

        };
        const response = await API.login(user);
        Auth.postLogin(response, { 
            ...user,
            name: response.name
        });
    }
},
checkAuthOptions: async (event) => {
    const response = await API.checkAuthOptions({
        email: document.getElementById("login_email").value
    });
    if (response.password) {
        document.getElementById("login_section_password").hidden = false;
    }
    if (response.webauthn) {
        document.getElementById("login_section_webauthn").hidden = false;
    }
    Auth.challenge = response.challenge;
    Auth.loginStep = 2;
},