Scenario-Based Questions

Definition

Questions presenting a broken application or a complex business requirement, testing how you apply Redux to solve it.

Explain Like I'm New

The interviewer gives you a real-world problem: 'Our app is dispatching 100 actions a second and the browser is crashing. Fix it.'

Real World Example

Explaining action batching or debouncing strategies.

Common Use Cases

•Practical problem solving

Terminal Output

bash / terminal

/* Q: We are migrating a massive legacy Redux app to RTK. We cannot rewrite the whole app at once. How do you approach this? A: RTK is 100% backwards compatible with legacy Redux! 1. I would start by replacing `createStore` with `configureStore`. This instantly adds Thunk and DevTools without breaking existing reducers. 2. For any NEW features, I will use `createSlice`. 3. I will slowly refactor old reducers into Slices one by one, as they can coexist perfectly in the same Root Reducer. */

Interview Questions

basic

You need to clear the entire Redux state when the user logs out. Where do you write this logic?

intermediate

A component uses `useSelector(state => state.app)`. Every time the user types in a completely unrelated form, this component re-renders. Why?

Flash Cards

Question

Where to clear state?

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Answer

In a Root Reducer wrapper. You intercept the `USER_LOGOUT` action at the very top level, and pass `undefined` into the `combineReducers` function, which forces every slice to reset to its initial state.

Question

Why re-render?

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Answer

Because `state.app` is an object. `useSelector` checks for reference equality (`===`). Every time the store updates (even from the typing form), the `app` object is technically a new object in memory. You must select primitive values (`state.app.status`), or use `shallowEqual`.