Q: Can a computed property be writable?

**Target Audience:** Vue developers who know read-only computed and want to know when a writable one is the right tool. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer expects. All output below was produced on Vue 3.5.44: the probe with node , the type errors with TypeScript 5 against Vue's own typings, and the component by compiling it with @vue/compiler-sfc<

Question 1

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 2

How do you render lists with v-for?

Accepted Answer

**Target Audience:** Beginners who need to show a list of things (products, messages, todos) in a Vue component. Basic JavaScript arrays and objects assumed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every rendered list, DOM-identity check and error message below came from mounting the code on Vue 3.5.44 in jsdom and clicking through it. ## 1. Why This Even Matters — A Story First Imagine you are writing place cards f

Question 3

How do you bind classes and styles dynamically?

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview. Assumes basic HTML and CSS and a first look at Vue templates.
**Difficulty:** Easy

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts that give you the exact vocabulary. Every rendered class string, style attribute, warning and compiler line quoted below came from running the code on Vue 3.5.44 (compiled with `@vue/compiler-sfc`, mounted in jsdom).

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

Imagine a

Question 4

How does Vue's reactivity system work?

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview — assumes basic JavaScript objects and functions, no Vue internals required. **Difficulty:** Medium > **How to read this doc:** Each idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. Every output block below was produced by running the code on Vue 3.5.44: plain reactivity with node, components compiled with @vue/compiler-s

Question 5

How do Transition and TransitionGroup work?

Accepted Answer

**Target Audience:** Developers comfortable with Vue templates and basic CSS transitions who want to know exactly what Vue does during an animation. **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 class sequences in section 4 were recorded on Vue 3.5.44 in jsdom with the repo's verify-vue-example.mjs harness. jsdom runs no CSS

Question 6

Why use storeToRefs with Pinia?

Accepted Answer

**Target Audience:** Anyone preparing for a Vue interview who has used [Pinia](/interview-question/what-is-pinia-and-why-use-it) at least once — basic ref and reactive knowledge 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. Every output was produced on Vue 3.5.44 with pinia 4.1.0 (and 3.0.4 for one compariso

Question 7

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 8

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

Accepted Answer

**Target Audience:** Vue 3 developers who know the [component v-model contract](/interview-question/how-does-v-model-work-on-components) and want to know what `defineModel()` really does.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. The compiled output is from `@vue/compiler-sfc` 3.5.44 `compileScript()`, and every value read after a click or keystroke came from mounting the components in jsdom on Vue 3.5.44. Version history comes

Question 9

How does v-model work on components?

Accepted Answer

**Target Audience:** Vue developers who use `v-model` on inputs and now need their own components to support it.
**Difficulty:** Medium

> **How to read this doc:** Plain language first, then `📌 Interview term:` callouts. The compiled output, warnings, compiler errors and the state after typing that are quoted below all came from Vue 3.5.44, compiled with `@vue/compiler-dom` and `@vue/compiler-sfc` and mounted in jsdom.

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

A hotel guest wants a differe

Question 10

Can a computed property be writable?

Accepted Answer

**Target Audience:** Vue developers who know read-only computed and want to know when a writable one is the right tool. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer expects. All output below was produced on Vue 3.5.44: the probe with node, the type errors with TypeScript 5 against Vue's own typings, and the component by compiling it with @vue/compiler-sfc<

VUE.JSDECODED.

Easy

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

How do you render lists with v-for?

How do you bind classes and styles dynamically?

Medium

How does Vue's reactivity system work?

How do Transition and TransitionGroup work?

Why use storeToRefs with Pinia?

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?

Can a computed property be writable?

How do you handle forms and validation in Vue?

Hard

When should you use shallowRef / shallowReactive / triggerRef?

What are common reactivity caveats in Vue?