Q: What is v-html and what is the risk of using it?

**Target Audience:** Beginners who have seen v-html in a codebase, or are tempted to use it. Basic HTML assumed; no security background needed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The rendered HTML was produced by mounting the example on Vue 3.5.44 in jsdom and with renderToString . Because jsdom does not load images (so an onerror payload can never fire there), the attack its

Q: What is a Single File Component (SFC)?

**Target Audience:** Beginners who have seen .vue files but do not know what is inside one or what happens to it. Basic HTML, CSS and JavaScript assumed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The compiled JavaScript and CSS in sections 5 and 6 are the real, unedited output of @vue/compiler-sfc 3.5.44, the same compiler @vitejs/plugin-vue calls during a Vite build. The runnable

Q: What is the difference between v-if and v-show?

**Target Audience:** Beginners who have used v-if or v-show and want to know which to pick. Basic HTML and CSS assumed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every DOM snapshot, lifecycle log and timing below was produced by mounting the code on Vue 3.5.44 in jsdom. The timings are jsdom numbers, useful for comparing the two directives with each other, not as real-browser figures. ## 1. Wh

Question 1

How do you handle events in Vue (v-on and event modifiers)?

Accepted Answer

**Target Audience:** Beginners wiring up buttons, forms and keyboard shortcuts in Vue. Basic DOM events (click, submit, keyup) assumed; no Vue experience needed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every "what got logged" table, compiled handler and ordering claim below was produced by dispatching real DOM events at components mounted on Vue 3.5.44 in jsdom. ## 1. Why This E

Question 2

What is Vue.js and what are its core features?

Accepted Answer

**Target Audience:** Complete beginners preparing for a first Vue interview. Assumes you know a little HTML and JavaScript, nothing about Vue or any other framework. **Difficulty:** Easy > **How to read this doc:** Every idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the exact words an interviewer listens for. The outputs in sections 5 and 6 were produced by actually compiling and running the code on Vue 3.5.44, the current stable r

Question 3

What is v-html and what is the risk of using it?

Accepted Answer

**Target Audience:** Beginners who have seen v-html in a codebase, or are tempted to use it. Basic HTML assumed; no security background needed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The rendered HTML was produced by mounting the example on Vue 3.5.44 in jsdom and with renderToString. Because jsdom does not load images (so an onerror payload can never fire there), the attack its

Question 4

What are props in Vue and how do you validate them?

Accepted Answer

**Target Audience:** Vue beginners who have built a component or two and now need them to accept configuration from a parent.
**Difficulty:** Easy

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. Every warning message, rendered value and production-build result quoted below came from running the code on Vue 3.5.44, compiled with `@vue/compiler-sfc` and mounted in jsdom, in development and production mode.

## 1. Why This Even Matters — A Story First

A coffe

Question 5

What are Vue directives? Give common examples.

Accepted Answer

**Target Audience:** Beginners who can read a basic Vue template and want to understand every v- attribute they see. Basic HTML and JavaScript assumed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The rendered output, the compiled render function and the warnings below come from compiling and mounting the example on Vue 3.5.44, not from memory. ## 1. Why This Even Matters — A Story First Imagine a theatre sc

Question 6

How do defineProps and defineEmits work in <script setup>?

Accepted Answer

**Target Audience:** Vue 3 developers using `<script setup>` who want to understand the two macros they write in almost every component.
**Difficulty:** Easy

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. All compiled output and compiler errors come from `@vue/compiler-sfc` 3.5.44 `compileScript()`; runtime logs from a two-component app compiled the same way and mounted in jsdom; type errors from `vue-tsc` 3.3.13.

## 1. Why This Even Matters — A Story Fir

Question 7

How do you create a new Vue 3 app, and what is in the project structure?

Accepted Answer

**Target Audience:** Beginners who have never set up a frontend project. Assumes Node.js is installed and you can type commands in a terminal; no Vue, Vite or build-tool knowledge needed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer expects. Nothing below is from memory: the project was generated by running create-vue 3.24.0 non-interactively in a sandbox, then installed, type-checked, bui

Question 8

What is a Single File Component (SFC)?

Accepted Answer

**Target Audience:** Beginners who have seen .vue files but do not know what is inside one or what happens to it. Basic HTML, CSS and JavaScript assumed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The compiled JavaScript and CSS in sections 5 and 6 are the real, unedited output of @vue/compiler-sfc 3.5.44, the same compiler @vitejs/plugin-vue calls during a Vite build. The runnable

Question 9

What is the difference between v-if and v-show?

Accepted Answer

**Target Audience:** Beginners who have used v-if or v-show and want to know which to pick. Basic HTML and CSS assumed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every DOM snapshot, lifecycle log and timing below was produced by mounting the code on Vue 3.5.44 in jsdom. The timings are jsdom numbers, useful for comparing the two directives with each other, not as real-browser figures. ## 1. Wh

Question 10

What are v-model modifiers?

Accepted Answer

**Target Audience:** Vue developers who already use `v-model` on inputs and want to control when and how values are stored.
**Difficulty:** Easy

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. Every value shown below was read from component state after a driver focused, typed into and blurred real inputs, on Vue 3.5.44 compiled with `@vue/compiler-sfc` and mounted in jsdom.

## 1. Why This Even Matters — A Story First

Think of a receptionist taking phone m

VUE.JSDECODED.

Easy

How do you handle events in Vue (v-on and event modifiers)?

What is Vue.js and what are its core features?

What is v-html and what is the risk of using it?

What are props in Vue and how do you validate them?

What are Vue directives? Give common examples.

How do defineProps and defineEmits work in <script setup>?

How do you create a new Vue 3 app, and what is in the project structure?

What is a Single File Component (SFC)?

Medium

What is Nuxt and how does it relate to Vue?

Pinia colocation in 2025 — how do you colocate stores with routes/components?

How does <Suspense> work in Vue 3.5 after the 2024 stabilization?

What are provide and inject?

What is defineModel() in Vue 3.4+ and how does it replace manual prop + emit?

How does v-model work on components?

How do you lazy-load routes and components in Vue?

How do you set up Vue Router (routes, RouterLink, RouterView, history modes)?

Hard

What is Vapor mode in Vue 3.5+ and how does it differ from the virtual DOM?

How do generic <script setup> components work (generic="T")?

What is Suspense in Vue?

How does defineAsyncComponent work with loading, error and retry in 2025?

What is a custom renderer in Vue (createRenderer)?

What is effectScope() and why do composables use it for cleanup?

How does server-side rendering work in Vue (renderToString, hydration)?