getInitialState() returning something weird followed by setState() has the world's worst error message

[petehunt]

See http://jsfiddle.net/nbJVN/

Return a string from getInitialState() and call setState(). You get this amazing error message:

Uncaught Error: Critical assumptions about the merge functions have been violated. This is the fault of the merge functions themselves, not necessarily the callers. 

[zpao]

We should probably add an invariant that whatever is returned from getInitialState is in fact an object.

[vjeux]

Invariant all the things :)

[dkvasnicka]

This also seems to apply when using an array, not the string only. Which makes it a pretty real-world bug IMHO (compared to the weird string scenario).
Or is there a reason you don't want states to be arrays?

[zpao]

This will happen whenever state is anything but an Object (I think there is a check in there for arrays). Since we use merge it needs to be an object, arrays are no good either.