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>
You can use the
v-else directive to indicate an "else block" for
<button @click="awesome = !awesome">Toggle</button> <h1 v-if="awesome">Vue is awesome!</h1> <h1 v-else>Oh no 😢</h1>
Vue is awesome!
v-else element must immediately follow a
v-if or a
v-else-if element - otherwise it will not be recognized.
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>
v-else-if element must immediately follow a
v-if or a
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 v-if="ok"> <h1>Title</h1> <p>Paragraph 1</p> <p>Paragraph 2</p> </template>
v-else-if can also be used on
Another option for conditionally displaying an element is the
v-show directive. The usage is largely the same:
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-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.
v-show is much simpler - the element is always rendered regardless of initial condition, with CSS-based toggling.
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.
It's not recommended to use
v-for on the same element due to implicit precedence. Refer to style guide for details.
v-for are both used on the same element,
v-if will be evaluated first. See the list rendering guide for details.