Question 1

What are scoped styles in Vue?

Accepted Answer

**Target Audience:** Vue developers who write `<style scoped>` and want to know precisely what it does and where its edges are.
**Difficulty:** Easy

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. The compiled CSS is real output from `@vue/compiler-sfc` 3.5.44 `compileStyle()` and from a `vite build` (vite 8.3.4, `@vitejs/plugin-vue` 6.0.10). The DOM attributes come from mounting the components in jsdom, and the computed colours were read from the built app

Question 2

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

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview who knows [what Pinia is](/interview-question/what-is-pinia-and-why-use-it) and has used lazy routes — mid-level and up. **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 chunk listings are real vite build output (Vite 8.3.4) of the small app whose files appear in the exam

Question 3

How do you make provide/inject type-safe?

Accepted Answer

**Target Audience:** Vue developers using TypeScript. Assumes you know what [provide and inject](/interview-question/what-are-provide-and-inject) do; this doc is only about typing them. **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 type errors quoted here are the real output of vue-tsc 3.3.13 on Vue 3.5.44, and the runtime ou

Question 4

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 5

What are provide and inject?

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview. Assumes you know props and `ref()`. **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 in the "Verified" sections was produced on Vue 3.5.44: the runnable example with the repo verifier (compiled and mounted in jsdom), the app-level behaviour with a Node script against the sam

Question 6

How do you use TypeScript with Vue (typed props, emits, refs, vue-tsc)?

Accepted Answer

**Target Audience:** Vue developers adopting TypeScript, or TypeScript developers new to Vue's single file components.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. Every type error below is real output from `vue-tsc` 3.3.13 with TypeScript 5.9 and `strict: true`; compiled output comes from `@vue/compiler-sfc` 3.5.44; runtime behaviour and warnings come from mounting the components in jsdom on Vue 3.5.44; the `vite build` result is

Question 7

What is defineExpose() and why are <script setup> components closed by default?

Accepted Answer

**Target Audience:** Vue developers who know template refs and are moving from the Options API to `

Question 8

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 9

How do Vue components communicate?

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview. Assumes basic JavaScript; no prior Vue knowledge needed. **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 quoted in the "Verified" sections was produced by running the code on Vue 3.5.44, either with the repo verifier (compiled with @vue/compiler-sfc and mounted

Question 10

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

VUE.JSDECODED.

Easy

What are scoped styles in Vue?

Medium