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

Question 1

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 2

What is Nuxt and how does it relate to Vue?

Accepted Answer

**Target Audience:** Vue developers who have heard of Nuxt and need to explain what it adds. No Nuxt experience assumed. **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. Everything in the "Verified" sections comes from a real Nuxt 4.6.1 project created for this answer: built with nuxt build, run as a production server, fetched with

Question 3

What is a Vue plugin?

Accepted Answer

**Target Audience:** Vue developers who install libraries with `app.use()` and want to write their own.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. The plugin, the component that uses it and `main.js` were bundled with esbuild and run in jsdom on Vue 3.5.44; every log line and warning below is that run's real output. API availability was checked against the published `@vue/runtime-core` type definitions.

## 1. Why This Even Matte

Question 4

useId() vs getCurrentInstance() — how do you generate SSR-safe IDs in Vue 3.5?

Accepted Answer

**Target Audience:** Vue developers building accessible forms or component libraries, especially with SSR or Nuxt.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. Every id and every warning below was produced on Vue 3.5.44: the component was mounted in jsdom and rendered with `renderToString`, three SSR requests were simulated in one Node process, and the HTML from one of them was hydrated in a fresh jsdom client. The `useId` source q

Question 5

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

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview — assumes basic Vue components, no routing experience required. **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. Every output block in this doc was produced by running the code on Vue 3.5.44 and vue-router 5.4.0: a real Vite 8 production build loaded into jsdom, Node scripts on the router

Question 6

How do you fetch data in a Vue component (loading, errors, cancellation)?

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview who knows [watch and watchEffect](/interview-question/what-is-the-difference-between-watch-and-watcheffect) and basic fetch — no data-fetching library required. **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. All output was produced on Vue 3.5.44. **No real network was used*

Question 7

How do you add global properties or config?

Accepted Answer

**Target Audience:** Vue developers setting up an app's entry file, or migrating `Vue.prototype` code from Vue 2.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. The runtime output below came from bundling the example (`main.js` plus three SFCs) with esbuild and running it in jsdom on Vue 3.5.44; the TypeScript errors came from `vue-tsc` 3.3.13 with `strict: true`.

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

Think of an office build

Question 8

What is Teleport in Vue 3?

Accepted Answer

**Target Audience:** Developers who build modals, toasts or popovers in Vue and have hit CSS clipping or stacking problems. **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. The DOM locations and warnings were produced by mounting the code on Vue 3.5.44 in jsdom with the repo's verify-vue-example.mjs harness, and the SSR output with

Question 9

How do you create a custom directive in Vue?

Accepted Answer

**Target Audience:** Vue developers who need low-level DOM behaviour they can reuse across templates. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every log line and warning below was printed on Vue 3.5.44 by mounting the SFCs in jsdom with the repo verifier (dev build), and the SSR output by renderToString from @vue/server-renderer. The typed example was checked with TypeScript 5 in strict mode

Question 10

What are composables in Vue?

Accepted Answer

**Target Audience:** Vue developers who know `ref` and `computed` and want to reuse logic properly.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. Every output in the "Verified" sections was produced by running the examples on Vue 3.5.44: the SFC was compiled and mounted in jsdom with the repo verifier, the plain-JavaScript example ran under Node.

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

Think of a power tool battery. You do not

VUE.JSDECODED.

Easy

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

Medium

What is Nuxt and how does it relate to Vue?

What is a Vue plugin?

useId() vs getCurrentInstance() — how do you generate SSR-safe IDs in Vue 3.5?

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

How do you fetch data in a Vue component (loading, errors, cancellation)?

How do you add global properties or config?

What is Teleport in Vue 3?

How do you create a custom directive in Vue?

Hard

What are v-once and v-memo?

How would you structure state management for a large Vue app?

What is lazy hydration in Vue 3.5 — hydrate strategies (idle, visible, interaction)?

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

How do you diagnose and fix hydration mismatches in Vue SSR / Nuxt 3?