conditional.md

Conditional Rendering {#conditional-rendering}

<script setup> import { ref } from 'vue' const awesome = ref(true) </script>

v-if {#v-if}

The directive v-if is used to conditionally render a block. The block will only be rendered if the directive's expression returns a truthy value.

<h1 v-if="awesome">Vue is awesome!</h1>

v-else {#v-else}

You can use the v-else directive to indicate an "else block" for v-if:

<button @click="awesome = !awesome">Toggle</button>

<h1 v-if="awesome">Vue is awesome!</h1>
<h1 v-else>Oh no 😢</h1>

Toggle

Vue is awesome!

Oh no 😢

Try it in the Playground

Try it in the Playground

A v-else element must immediately follow a v-if or a v-else-if element - otherwise it will not be recognized.

v-else-if {#v-else-if}

The v-else-if, as the name suggests, serves as an "else if block" for v-if. It can also be chained multiple times:

<div v-if="type === 'A'">
  A
</div>
<div v-else-if="type === 'B'">
  B
</div>
<div v-else-if="type === 'C'">
  C
</div>
<div v-else>
  Not A/B/C
</div>

Similar to v-else, a v-else-if element must immediately follow a v-if or a v-else-if element.

v-if on <template> {#v-if-on-template}

Because v-if is a directive, it has to be attached to a single element. But what if we want to toggle more than one element? In this case we can use v-if on a <template> element, which serves as an invisible wrapper. The final rendered result will not include the <template> element.

<template v-if="ok">
  <h1>Title</h1>
  <p>Paragraph 1</p>
  <p>Paragraph 2</p>
</template>

v-else and v-else-if can also be used on <template>.

v-show {#v-show}

Another option for conditionally displaying an element is the v-show directive. The usage is largely the same:

<h1 v-show="ok">Hello!</h1>

The difference is that an element with v-show will always be rendered and remain in the DOM; v-show only toggles the display CSS property of the element.

v-show doesn't support the <template> element, nor does it work with v-else.

v-if vs. v-show {#v-if-vs-v-show}

v-if is "real" conditional rendering because it ensures that event listeners and child components inside the conditional block are properly destroyed and re-created during toggles.

v-if is also lazy: if the condition is false on initial render, it will not do anything - the conditional block won't be rendered until the condition becomes true for the first time.

In comparison, v-show is much simpler - the element is always rendered regardless of initial condition, with CSS-based toggling.

Generally speaking, v-if has higher toggle costs while v-show has higher initial render costs. So prefer v-show if you need to toggle something very often, and prefer v-if if the condition is unlikely to change at runtime.

v-if with v-for {#v-if-with-v-for}

::: warning Note It's not recommended to use v-if and v-for on the same element due to implicit precedence. Refer to style guide for details. :::

When v-if and v-for are both used on the same element, v-if will be evaluated first. See the list rendering guide for details.