DefineAuthChallenge.js

exports.handler = async (event) => {
    console.log('-- event', JSON.stringify(event))
    if (!event.request.session || event.request.session.length === 0) {
        // If we don't have a session or it is empty then send a CUSTOM_CHALLENGE
        event.response.challengeName = "CUSTOM_CHALLENGE";
        event.response.failAuthentication = false;
        event.response.issueTokens = false;
    } else if (event.request.session.length === 1 && event.request.session[0].challengeResult === true) {
        // If we passed the CUSTOM_CHALLENGE then issue token
        event.response.failAuthentication = false;
        event.response.issueTokens = true;
    } else {
        // Something is wrong. Fail authentication
        event.response.failAuthentication = true;
        event.response.issueTokens = false;
    }

    return event;
};