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

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 2

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 3

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 4

How do you optimize performance in a Vue app?

Accepted Answer

**Target Audience:** Vue developers who have shipped an app and now need a method for making it faster. Assumes the Composition API basics. **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 number here was measured for this answer on Vue 3.5.44: the re-render counts by mounting the runnable example in jsdom with scripts/verify-vue-exa

Question 5

What is a custom renderer in Vue (createRenderer)?

Accepted Answer

**Target Audience:** Vue developers curious about how Vue is structured internally, or evaluating Vue for a non-DOM target (canvas, 3D, terminal, native). **Difficulty:** Hard > **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 runnable example passed scripts/verify-vue-example.mjs on Vue 3.5.44 (compiled and mounted in jsdom, button clicked). The termin

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Easy

What are Vue directives? Give common examples.

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

Medium

How do Transition and TransitionGroup work?

How do you optimize performance in a Vue app?

Hard

What is a custom renderer in Vue (createRenderer)?