Switch to therubyracer and general questions about what JS engine about react_on_rails

[samnang]

1. I curious as to the purpose of eval vs. compile methods in the execJS?

They basically the same thing, eval will unbox the result and convert into ruby values.
https://github.com/rails/execjs/blob/master/lib%2Fexecjs%2Fruntime.rb#L38-L44
https://github.com/rails/execjs/blob/master/lib%2Fexecjs%2Fruby_racer_runtime.rb#L13
https://github.com/rails/execjs/blob/master/lib%2Fexecjs%2Fruby_racer_runtime.rb#L34

2. Any advice on what's going the be best performance for rendering react components server side?

I'm not sure, but we definitely doesn't want to instantiate engine every render and request. Yes, execjs is just universal wrapper for V8 javascript engine, it will auto-detect to select the best one. And here is the order https://github.com/rails/execjs/blob/master/lib%2Fexecjs%2Fruntimes.rb#L77

[justin808]

@samnang Great answer. Looks like we just need folks to be sure that V8 is installed. I updated the readme.