What is a slot?
- It’s a space in your component output that is reserved, waiting to be filled.
- You define a slot by putting <slot></slot> in a component template:
<template>
<div class="User-information">
<slot></slot>
</div>
</template>
- When using this component, any content added between the opening and closing tag will be added inside the slot placeholder:
<user-information>
<h2>Hi!</h2>
<user-name name="Flavio"></user-name>
</user-information>
- If you put any content side the <slot></slot> tags, that serves as the default content in case nothing is passed in.
- A complicated component layout might require a better way to organize content, with multiple slots as well.
- This is why Vue.js offers us named slots.
Named slots
- With a named slot you can assign parts of a slot to a specific position in your component template layout, and you use a slot attribute to any tag, to assign content to that slot.
- Anything outside any template tag is added to the main slot .
- For convenience I use a page single file component in this example:
<template>
<div>
<main>
<slot></slot>
</main>
<aside>
<slot name="sidebar"></slot>
</aside>
</div>
</template>
- Here is how we can use it, providing the slots content, in a parent component:
<page>
<template v-slot:sidebar>
<ul>
<li>Home</li>
<li>Contact</li>
</ul>
</template>
<h2>Page title</h2>
<p>Page content</p>
</page>
- There is a handy shorthand :
<page>
<template #sidebar>
<ul>
<li>Home</li>
<li>Contact</li>
</ul>
</template>
<h2>Page title</h2>
<p>Page content</p>
</page>
Scoped slots
- In a slot, we can’t access the data contained in the child component from the parent.
- Vue.js recognizes this use case and provides us a way to do so:
<template>
<div>
<main>
<slot v-bind:dogName="dogName"></slot>
</main>
</div>
</template>
<script>
export default {
name: 'Page',
data: function() {
return {
dogName: 'Roger'
}
}
}
</script>
- In the parent we can access the dog name we passed using:
<page>
<template v-slot="slotProps">
{{ slotProps.dogName }}
</template>
</page>
- Slotprops is just a variable we used to access the props we passed. You can also avoid setting a variable just to hold the props you pass to the child component, by destructuring the object on the fly:
<page>
<template v-slot="{ dogName }">
{{ dogName }}
</template>
</page>
