Can Google properly crawl my pages if they are inaccessible without facebook login?

The title pretty concisely states my problem. I’ve built a dating app that requires a user to login through Facebook before they can access any other pages and parts of my dating site (search, account page, messages, etc). Once a user is authenticated using the ‘Meteor.loginWithFacebook’ method, I then show the navigation bar.

Is this bad for SEO? Is Google able to still somehow crawl my site? I’ve heard some people say that Google can still somehow login with Facebook to properly crawl your site but am not entirely sure. I’ve heard SPAs and Meteor have problems with SEO and Google crawling them even though their crawlers will run Javascript.

Regardless of your answers, any tips on what I can do to help with SEO and helping Google at least crawl the 5 primary ‘pages’ of my site (via a sitemap or whatever) is appreciated. I’ve been using the OK:Grow package and at least running the ‘analytics.page()’ function on my routes.