useReducer hook in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the useReducer hook used for in React Native?

useReducer helps manage complex state logic by using a reducer function to update state based on actions.

beginner

What are the two main parts you provide to useReducer?

You provide a reducer function and an initial state.

intermediate

Explain the role of the reducer function in useReducer.

The reducer function takes the current state and an action, then returns a new state based on that action.

beginner

How do you dispatch an action in useReducer?

You call the dispatch function with an action object, like { type: 'increment' }.

intermediate

Why might you choose useReducer over useState?

Use useReducer when state logic is complex or involves multiple sub-values and actions.

What does the useReducer hook return?

A An array with state and dispatch function

B Only the current state

C Only the dispatch function

D A boolean indicating success

useReducer returns an array with the current state and a dispatch function to send actions.

Which argument is NOT passed to the reducer function?

A Dispatch function

B Action object

C Current state

D None of the above

The reducer function receives only the current state and the action object, not the dispatch function.

How do you define an action for useReducer?

A A string

B An object with a <code>type</code> property

C A number

D A boolean

Actions are objects with a type property describing what to do.

Which hook is better for simple state updates?

A useReducer

B useEffect

C useState

D useContext

useState is simpler and better for basic state updates.

What happens if the reducer returns the same state object?

A State resets

B React re-renders anyway

C App crashes

D React skips re-render

If the reducer returns the same state object, React skips re-rendering for performance.

Describe how to set up and use the useReducer hook in a React Native component.

Think about the reducer signature and how you call dispatch.

Explain when and why you would prefer useReducer over useState in managing component state.

Consider the complexity of state changes.