SW versioning

I pulled down the latest version 6 of Choo using create-Choo-app. I love the work.

This might be a question for bankai. Running npm build leaves the sw.js in the top dir. Are you planning on integrating sw.js versioning and cp to build directory? (I think we discussed this on twitter) I've linked to a quick YouTube of supercharged js which uses gulp to do this

https://m.youtube.com/watch?v=ruKbxoFACp8

Start with the create-Choo-app npm build flow and inspect where sw.js is emitted. Determine whether service-worker versioning and copying into the build directory belong here or in bankai. Done means the intended ownership and behavior are defined, with the build output matching that decision.

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