add support of undefined type in initialState

[lhr000lhr]

previous version support put undefined in initialState,
after upgrading to the latest version, Foca shows the error

[geekact]

undefined is unsafe when using persistence feature.

const data  = { x: undefined, y: 1 };
const data1 = JSON.parse(JSON.stringify(data)); // { y: 1 }

Maybe I should only limit the models which want to use persistence instead of all models.

[geekact]

What's the case you have to input undefined key ? We know that value will always be undefined when you are visiting a non-exists key. My suggestion is do not explicit set a key whose value is undefined

[geekact]

Anyway, I have published version 0.12.2 to fix this issue. Good luck.

[lhr000lhr]

thanks, man.