React-Redux: Should all component states be kept in Redux Store

For the purpose of highlighting the great link provided by @AR7, and because that link moved a while back:

Use React for ephemeral state that doesn't matter to the app globally and doesn't mutate in complex ways. For example, a toggle in some UI element, a form input state. Use Redux for state that matters globally or is mutated in complex ways. For example, cached users, or a post draft.

Sometimes you'll want to move from Redux state to React state (when storing something in Redux gets awkward) or the other way around (when more components need to have access to some state that used to be local).

The rule of thumb is: do whatever is less awkward.

Dan Abramov:

Redux FAQ: Organizing State
this part of redux official doc well answered your question.

Using local component state is fine. As a developer, it is your job to determine what kinds of state make up your application, and where each piece of state should live. Find a balance that works for you, and go with it.

Some common rules of thumb for determining what kind of data should be put into Redux:

  • Do other parts of the application care about this data?
  • Do you need to be able to create further derived data based on this original data?
  • Is the same data being used to drive multiple components?
  • Is there value to you in being able to restore this state to a given point in time (ie, time travel debugging)?
  • Do you want to cache the data (ie, use what's in state if it's already there instead of re-requesting it)?

Redux is primarily intended for "application state." That is, anything related to your application logic. The view built on top of it is a reflection of that state, but does not have to exclusively use that state container for everything it does.

Simply ask these questions: Is this state important to the rest of the application? Will other parts of the application behave differently based on that state? In many minor cases, that will not be the case. Take a drop down menu: The fact that it's open or closed probably won't have an effect on other parts of the app. So, wiring it up to your store is probably overkill. It's certainly a valid option, but doesn't really net you any benefits. You're better off using this.state and calling it a day.

In your particular example, does the color that button is toggled to make any difference in other parts of the application? If it's some sort of global on/off toggle for a major part of your application, it definitely belongs in the store. But if you're just toggling a button color when you click the button, you can leave the color state locally-defined. The action of clicking the button might have other effects that require an action dispatch, but that is separate from the simple question of what color it should be.

In general, try to keep your application state as small as possible. You don't have to shove everything in there. Do it when you have to or it makes a lot of sense to keep something there. Or if it makes your life easier when using Dev Tools. But don't overload its importance too much.