Comment by dustingetz

This is called interactive development; if you liked this, check these out:

* Interactive programming Flappy Bird in ClojureScript: https://www.youtube.com/watch?v=KZjFVdU8VLI

* Live-editing React app without refresh: https://vimeo.com/100010922

These demos aren't smoke and mirrors, I and many others do interactive development, 8 hours a day, writing regular web apps.