join-event-promises.js

function joinEvent(email, password, event) {
    login(email, password).then(user => {
        return getUserInfo(user);
    }).then(userInfo => {
        return event.join(userInfo.id);
    }).then((success) => {
        if (success) {
            console.log("Joined!");
        }
        else {
            console.log("Not Joined");
        }
    })
}