Contextual Switches

[hamlim]

This is a pretty common feature of most feature flag / feature toggle systems (and even experimentation platforms too). At the time of writing, switch-kit is agnostic of who or what is trying to determine the value of the switch. That works well for distributing "universal" switch state, but it doesn't if we want to support experimentation, or different evaluations of a switch for different contexts (where a context could be almost anything, think some unique device ID, or a user ID, or even for different domains etc).

I don't yet have a good idea for how to completely implement this - however my assumption is that it'll need 2 core parts:

1. An additional argument on SwitchKit.get(switchName, context)
2. A "decision engine" within the Adaptor (determines which value to use based on the context, and also manages persisting that decision on the switch metadata)