What does a typical action object look like?

Difficulty: 4/10

action shape, payload conventions, type prefixing

In Redux, an action is a plain JavaScript object that describes what event occurred in the app. Each action must have a type field that identifies the kind of operation being performed, and it can optionally include a payload carrying additional data.

Key Components of an Action Object

1
type: A string that uniquely identifies the action, often namespaced by slice (e.g., counter/increment).
2
payload: Optional data that provides information needed by the reducer to update the state.
3
and : Optional fields used for advanced use cases like async operations or error handling.

Example: Typical Action Object

Scenario Questions

0-2 years experience

1You're adding a new button that dispatches an async thunk. How would you structure the action object that the thunk returns on success?
2If you look at Redux DevTools and see an action with type 'user/login' but no payload, what does that tell you about how the action was created?
3When a reducer generated by createSlice runs, what fields does the incoming action object contain?

Follow-up Questions

Can you show a concrete example of an action created by createAction?
What changes in the object when an async thunk is rejected?
How would you add custom metadata without breaking existing reducers?