NativeScript for Mobile App Development State Management and Application Architecture 3

Question 1

When implementing Redux with NativeScript, what is the role of a 'reducer' function?

Accepted Answer

It takes the current state and an action and returns a new state

Answer

A reducer is a pure function that takes the current state and a dispatched action as arguments and returns the next state without mutating the original.

Question 2

In NativeScript, what is the primary advantage of using ObservableArray over a regular JavaScript array for list data?

Accepted Answer

ObservableArray automatically notifies ListView of item additions, removals, and changes

Answer

ObservableArray emits change events when items are added, removed, or replaced, enabling ListView and Repeater to update automatically without manual refresh.

Question 3

What is 'property change batching' in the context of NativeScript Observable state updates?

Accepted Answer

Grouping multiple property changes to minimize UI re-renders

Answer

Batching multiple Observable property changes before notifying the UI reduces unnecessary re-renders, improving performance when updating several state values at once.

Question 4

Which NativeScript feature enables two different pages/modules to communicate state changes without a direct reference to each other?

Accepted Answer

The global application event bus using Application.on()/off()

Answer

NativeScript's Application object provides a global event bus (on/off/notify) allowing loosely coupled modules to publish and subscribe to state-change events.

Question 5

In a NativeScript app, what problem does the 'single source of truth' principle solve?

Accepted Answer

It prevents multiple conflicting copies of the same state across the app

Answer

Maintaining one authoritative state store prevents inconsistencies that arise when multiple components hold independent copies of the same data that can drift out of sync.

NativeScript for Mobile App Development Practice Test

NativeScript for Mobile App Development Practice Test

NativeScript for Mobile App Development State Management and Application Architecture 3