How can I debug triggers of reactive computations in Blaze?

Hi.

I am using Iron Router.
When you set layout property for some route, helper functions are called several times for page rendering.

Actually, they are called before and after onRendered of layout template, and before onCreated of template for yield.

I wonder if it may be a bug in Iron Router, but it seems not to maintain any more.

I want to try to debug it, but I have no idea to search trigger of helper functions.

Does anyone give me hints?
Of cource, I will appreciate if you fix this problem.

Thanks.

Self follow up.

Google Chrome’s debugger enabled me to trace stacks even behond async postMessage.

And I found that Iron Router let all helpers to recompute when receiving data().
I moved all template instances that do not depend on data() into body template rather than layout template and succeeded to avoid useless recomputations.