[轉]跟著小明一起搞懂技術名詞：MVC、SPA 與 SSR
https://medium.com/@hulitw/introduction-mvc-spa-and-ssr-545c941669e9
Angular2
[轉]如何在 Angular CLI 建立的 Angular 2 開發環境呼叫遠端 RESTful APIs
http://blog.miniasp.com/post/2017/02/05/Setup-proxy-to-backend-in-Angular-CLI.aspx
angular ES2017
https://egghead.io/courses/asynchronous-javascript-with-async-await
angular2 Observables
http://codin.im/2016/09/17/observables-in-angular2-translate/
angularfire2 subscribe once
https://github.com/angular/angularfire2/issues/380 subscription.unsubscribe(); Observable.interval + take(1)