Vue.js Interview Questions & Answers

What is a Vue component?

Options API vs Composition API?

What does <script setup> give you?

Single-file component structure best practices?

How do async components work in Vue?

What is Vue Suspense used for?

Functional vs stateful components in Vue 3?

How do slots enable composition?

When do you use keep-alive?

Teleports — what problem do they solve?

Recursive components — when and pitfalls?

Design a reusable DataTable component API in Vue.

How does Vue 3 reactivity work?

ref vs reactive — when each?

What does computed do?

watch vs watchEffect?

Why does destructuring props break reactivity and how do you fix it?

shallowRef / shallowReactive — when?

What is markRaw?

Triggering updates with Map/Set?

effectScope — what is it for?

How do you debug unexpected re-renders/updates?

Readonly proxies — why use readonly()?

Architecture: model a complex form with Vue reactivity.

What is a composable in Vue?

Lifecycle hooks in setup / script setup?

How do provide/inject work with Composition API?

Top-level await in <script setup> — implications?

Sharing state with a module-level ref composable?

Composable design best practices?

How do you migrate an Options API component to Composition?

defineExpose — when do you need it?

TypeScript with defineProps/defineEmits?

Composables vs Pinia stores?

How do you unit test a composable?

Lead: standards for composables in a large Vue codebase?

How do props work in Vue 3?

How do emits work?

How does v-model work on components?

Props validation — runtime vs TypeScript?

Fallthrough attributes — what are they?

When to use prop drilling vs provide/inject vs Pinia?

Boolean props casting quirks?

Design events for a complex picker component.

one-way data flow — why does Vue emphasize it?

How do you type v-model with TypeScript?

What are Vue directives?

v-if vs v-show?

v-for key best practices?

v-model modifiers — .lazy .number .trim?

What does v-bind / v-on shorthand look like?

Custom directives — when preferred over components?

Directive hooks in Vue 3 (created/mounted/updated/...)?

v-html security concerns?

v-memo — what does it do?

Common v-for + v-if pitfall?

How does Vue Router map paths to views?

Params vs query in Vue Router?

Navigation guards — beforeEach vs beforeEnter vs in-component?

How do you lazy load routes?

Nested routes and named views?

How do you scroll restore / scroll behavior?

Passing props to route components?

Dynamic route matching and catch-all?

Composition API: useRouter and useRoute?

Architecture for large Vue apps' routing?

What is Pinia?

Options store vs setup store?

How do you persist Pinia state?

Why prefer multiple stores over one mega-store?

Getters in Pinia — best practices?

Actions async patterns?

Using stores outside components?

Pinia vs provide/inject for shared state?

How do store plugins help?

Lead: state management guidelines with Pinia?

Key Vue 3 performance techniques?

Why can huge reactive objects be costly?

List rendering performance tips?

How does Vite help Vue app performance in practice?

Avoiding unnecessary component updates?

SSR/SSG performance considerations for Vue?

Images and fonts in Vue SPAs?

Lead: performance culture on a Vue team?

How do you structure a scalable Vue 3 app?

Container vs presentational components in Vue?

When choose Nuxt vs plain Vite+Vue?

Handling API clients cleanly?

Microfrontends with Vue — considerations?

Error handling strategy across the app?

Design auth flow architecture in Vue.

Lead: migrating a Vue 2 app to Vue 3?

How do you test Vue components with Vue Test Utils?

Testing Pinia stores?

How do you test composables that use lifecycle hooks?

Snapshot tests — useful or harmful?

E2E testing Vue apps?

Mocking Vue Router in unit tests?

How do you test async components / Suspense?

Lead: testing strategy for a Vue product team?