HistoryJSMixin updated: React History / PushState now with URL updates (great for pagination / search)

I wanted a simple way for React component state to update pushState/history, and I found it in Leif Denby's simple HistoryJSMixin. One thing it was missing: being able to update the URL too (e.g. change "/foo" to "/foo?bar=baf") with that state. 

I've added it with a simple two line change here (line 57 and 61): 

Here's an example snippet of how to use it:

So, as you can see on line 10, you can pass a url key to the call now and have it propagate to the URL bar. I've been using it in places where React Router would be too heavy duty, and all you really want is to propagate search terms, or page number.

LazyGenerate: How to lazily generate properties in ActiveRecord

At times in the Posterous days we wanted to add new properties but a migration would be prohibitively expensive given a large corpus of data.

Here's a simple module you can include in your ActiveRecord objects to do just that — lazily generate potentially costly computation and save it to an object only when it is actually called. 

Dragons in these hills — but sometimes you want that. We're going to steer clear of these kinds of hacks for Posthaven, but as a minor exercise in metaprogramming maybe this'll be useful in the future: