The initial is mutated

[vbuch]

When a state is created, one could pass in an inital value. If that initial value is an object, it is later mutated when calling set or merge.

Repro: https://codepen.io/vbuch/pen/BaxzeZY?editors=0011

I'm fine with just having this documented. But it took me quite some time to figure where my data gets messed up.

[avkonst]

yes, hookstate works on mutable object

[avkonst]

documented in concepts https://hookstate.js.org/docs/getting-started