v-if directive behavior in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the v-if directive do in Vue?

The v-if directive conditionally renders an element or component only if the given expression is true. If false, the element is not added to the DOM.

intermediate

How does v-if differ from v-show?

v-if adds or removes elements from the DOM based on the condition, while v-show only toggles the CSS display property without removing the element.

intermediate

What happens to event listeners and child components when v-if condition becomes false?

When v-if is false, the element and its children are removed from the DOM, so event listeners and child component instances are destroyed.

advanced

Can you use v-if on a <template> tag? Why?

Yes, v-if can be used on a <template> tag to conditionally render multiple elements without adding an extra wrapper element to the DOM.

intermediate

What is the impact of using multiple v-if directives on sibling elements?

Each v-if directive controls its own element independently, so multiple siblings with v-if can be conditionally rendered separately based on their own expressions.

What happens when a v-if condition is false?

A The element is removed from the DOM

B The element is hidden with CSS

C The element stays visible

D The element is disabled

v-if removes the element from the DOM when the condition is false.

Which directive toggles element visibility without removing it from the DOM?

A v-for

B v-if

C v-show

D v-bind

v-show toggles the CSS display property but keeps the element in the DOM.

Can v-if be used on a <template> tag?

A No, it only works on elements

B Yes, to conditionally render multiple elements without extra wrappers

C Yes, but it adds an extra wrapper element

D No, it causes errors

Using v-if on <template> allows conditional rendering of multiple elements without adding extra DOM nodes.

What happens to child components inside a v-if block when the condition becomes false?

A They keep running in the background

B They stay mounted but hidden

C They become disabled

D They are destroyed and removed from the DOM

Child components inside a v-if block are destroyed when the condition is false.

If two sibling elements each have their own v-if, how are they rendered?

A Each is rendered based on its own condition

B Both are always rendered

C Only the first is rendered

D Neither is rendered

Each sibling with v-if is rendered independently based on its own condition.

Explain how the v-if directive controls rendering in Vue and how it affects the DOM.

Think about what happens when the condition is true versus false.

Describe the difference between v-if and v-show and when you might use each.

Consider performance and DOM presence.