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Linda
Linda

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Conditional Rendering in Vue

Vue Logo with text Conditional rendering

Conditional rendering is a term to describe the ability to render different user interface (UI) markup depending on if a condition is true or false.

Conditional Rendering can be implemented in Vue using the directives below

πŸ’š v-if

πŸ’š v-else

πŸ’š v-else-if

πŸ’š v-show

v-if

The "v-if" directive can used to conditionally render an element including other elements that may be within it. The block will only be rendered if the directive’s expression returns a truthy value.

Example

<h1 v-if="showGreeting">Welcome Home!</h1>
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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?

You can also add conditional rendering to a group of elements by wrapping them in a "" element as shown below

<template v-if="Chores"> πŸ™ƒ
    <h1>Chores</h1>
    <ul>
        <li>Wash the cat</li>
        <l1>Do the dishes</li>
    <ul>
</template>
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"" element serves as an invisible wrapper and will not be displayed in the final rendered result.

v-else

The "v-else" directive can only be used immediately after the "v-if" directive. They follow the pattern of a typical if-else statement.

The content within the "v-else" element will be rendered if the condition set in the "v-if" element is not met.

<template v-if="Chores"> πŸ™ƒ
    <h1>Chores</h1>
    <ul>
        <li>Wash the cat</li>
        <l1>Do the dishes</li>
    <ul>
</template>
<h1 v-else> Watch television</h1> πŸ˜€
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v-else-if

The "v-else" element gives you only one other option to render if "v-if" element's condition is not met.

"v-else-if" serves as an else-if block for "v-if". It can also be chained multiple times so it enable you to have more than one option to render.

<template v-if="Chores"> πŸ™ƒ
    <h1>Chores</h1>
    <ul>
        <li>Wash the cat</li>
        <l1>Do the dishes</li>
    <ul>
</template>
<h1 v-else-if="Homework"> Do homework</h1>
<h1 v-else> Watch television</h1> πŸ˜€
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v-show

"v-show" is very similar to "v-if"

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" does not work in the "template" element nor does it work with "v-else".

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

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