Conditional Rendering | Vue.js

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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.
You can use the v-else directive to indicate an "else block" for v-if:
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.
The v-else-if, as the name suggests, serves as an "else if block" for v-if. It can also be chained multiple times:
Similar to v-else, a v-else-if element must immediately follow a v-if or a v-else-if element.
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.
v-else and v-else-if can also be used on <template>.
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-else.
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.
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.
It's not recommended to use v-if and v-for on the same element due to implicit precedence. Refer to list rendering guide for details.
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