2-pass system

[amcdnl]

Investigate whether a 2-pass system would be more ideal. I'm not sure since it might try to over-optimize though and end up with huge bundles.

Idea from: https://www.youtube.com/watch?v=C-kM0v9L9UY&feature=youtu.be

[lookfirst]

I was just reading the documentation and wondering why we didn't use this approach:

https://github.com/systemjs/builder#example---trace-builds

It feels like we just build up the routes as individual trace()'s and then intersect the trees.

[amcdnl]

This must be new. I haven't seen this before ....

@marjan-georgiev - any thoughts?

[marjan-georgiev]

We are using that approach though. Using trace to pull dependency trees for individual modules, and then running an algorithm to calculate the bundles.

[marjan-georgiev]

I'll need to run some benchmarks on that second pass that stealjs does. That's tricky to get right, and it really depends on the nature of the project. In some cases it might do more harm than good.

[lookfirst]

Oh yea, I just noticed the trace() usage too. Sorry about that! =)

One question, what is the difference between the treeCache and treeIndex? https://github.com/Swimlane/systemjs-route-bundler/blob/master/lib/tree-walker.js#L24