Vue JS Vue JS Performance Optimization 2

Question 1

What is the recommended approach to avoid expensive computations running on every render in Vue?

Accepted Answer

Use computed() to cache the result until reactive dependencies change

Answer

computed properties are cached based on their reactive dependencies and only recalculate when a dependency changes, preventing redundant computation on every render.

Question 2

Which Vue DevTools feature helps identify which components are re-rendering unnecessarily?

Accepted Answer

Component timeline / performance profiler

Answer

Vue DevTools' Performance tab / Timeline shows component render timings and highlights components that re-render, helping identify wasted renders.

Question 3

How can you defer rendering of off-screen or non-critical components to improve initial load in Vue?

Accepted Answer

Use async components with defineAsyncComponent()

Answer

defineAsyncComponent() creates a component that is only loaded from the server when it is first rendered, and can include loading/error states.

Question 4

What is the benefit of using functional components in Vue for performance-sensitive rendering?

Accepted Answer

They have no reactive state or lifecycle hooks, making them lighter and faster to render

Answer

Functional components are stateless and instanceless, so Vue skips creating a component instance, reducing memory use and rendering overhead.

Question 5

Why should you avoid using v-if and v-for on the same element in Vue?

Accepted Answer

v-if has higher priority in Vue 3, causing each iteration to re-evaluate the condition needlessly

Answer

In Vue 3 v-if takes priority over v-for, meaning the condition is checked before the list can be iterated; this is confusing and inefficient — use a computed array instead.

Vue JS Practice Test

Vue JS Practice Test

Vue JS Vue JS Performance Optimization 2