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<

Q: What is useTemplateRef() (Vue 3.5) and how does it improve on ref=""?

**Target Audience:** Vue developers who already use template refs and want to know what changed in 3.5. The general rules for refs (timing, `v-for`, component instances) are in [accessing a DOM element or child component instance](/interview-question/how-do-you-access-a-dom-element-or-child-component-instance). **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 interviewe

Q: What do toRef and toRefs do?

**Target Audience:** Vue developers who know ref and reactive and keep seeing toRefs in composables without being sure what it buys them. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every output below was produced on Vue 3.5.44: the probe with node , the component compiled with @vue/compiler-sfc and clicked in jsdom. The source excerpt is copied from the in

Question 1

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 2

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 3

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<

Question 4

What is useTemplateRef() (Vue 3.5) and how does it improve on ref=""?

Accepted Answer

**Target Audience:** Vue developers who already use template refs and want to know what changed in 3.5. The general rules for refs (timing, `v-for`, component instances) are in [accessing a DOM element or child component instance](/interview-question/how-do-you-access-a-dom-element-or-child-component-instance). **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 interviewe

Question 5

What does readonly do in Vue's reactivity?

Accepted Answer

**Target Audience:** Vue developers who share state between components, stores or composables. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every warning message and value below was printed by running the code on Vue 3.5.44, both as Node scripts against the vue package and as an SFC mounted in jsdom. This page explains **what** readonly does. For **when** to use it next to markRaw a

Question 6

What do toRef and toRefs do?

Accepted Answer

**Target Audience:** Vue developers who know ref and reactive and keep seeing toRefs in composables without being sure what it buys them. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every output below was produced on Vue 3.5.44: the probe with node, the component compiled with @vue/compiler-sfc and clicked in jsdom. The source excerpt is copied from the in

Question 7

When should you use readonly, markRaw, and toRaw in Vue reactivity?

Accepted Answer

**Target Audience:** Vue developers designing composables and stores, or integrating non-Vue libraries. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Warnings, outputs and timings below come from running code on Vue 3.5.44 (Node 22, and jsdom for the component); timings are from one sandbox machine. This page is the **decision guide**. The mechanics are covered by two sibling questions: [What does readonly do in Vue's rea

Question 8

What do markRaw and toRaw do?

Accepted Answer

**Target Audience:** Vue developers integrating third-party objects or debugging identity bugs in reactive state. **Difficulty:** Hard > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every value and error message below was printed by running the code on Vue 3.5.44 in Node 22, or by mounting the SFC in jsdom with the repo verifier. This page explains **how** markRaw and toRaw work. For **when** to choose them, alongside <

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