fix fetching initial state from redux store

[marzelin]

Subscription takes place after Redux store initialization action so listener won't update component's initial state - the app state needs to be synchronized manually.

[vkarpov15]

Thanks for the PR. What effects does this issue have?

[marzelin]

In your checkbox example where the checkbox is initially in unchecked state it's not because the state in redux store is false (the store state is not fetched at this point), but because this.state is an empty object as initially declared in constructor (you can see it in react tools). The end result is still the same - checkbox is initially rendered as unchecked, but for quite different reasons.

Knowing that a callback given to store.subscribe() won't be fired on store initialization is a minor detail since normally everybody uses connect() to wire store to components, but still worth noting when playing with Redux's lower level interface.

btw great course.

[vkarpov15]

Good catch, thanks for your PR 🍻