Vue Js Slot Props

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Vue.js - The Progressive JavaScript Framework. One-Way Data Flow. All props form a one-way-down binding between the child property and the parent one: when the parent property updates, it will flow down to the child, but not the other way around. This prevents child components from accidentally mutating the parent's state, which can make your app's data flow harder to understand. Vue 2.6 (v-slot syntax) All ordinary slots will be added to scoped slots, so you only need to do this. How to DRY use a Vue.js component with multiple props. Vue.js で slot を使ったコンポーネントの持つ値を、slot に差し込まれるコンポーネントに props として渡す方法を調べました。 slot を使ったコンポーネントを Hoge コンポーネント、差し込むコンポーネントを Fuga コンポーネントとすると、以下の感じでいけます。.

Vue 2.6 is released with new syntax for Slots using v-slot directive. In this tutorial, we’re gonna show you:

Let’s go over the renderless slot pattern in Vue and see the problems that it can help solve. Introduced with Vue.js 2.3.0, scoped slots have considerably improved component reusability. For example, the renderless component pattern emerged and solved the problem of providing reusable behavior and pluggable presentation. Vue.js has slots in order to make components have a redefinable structure, but by themselves they're pretty limited. Sometimes you need some data or state in order to define how a component should render. If you don't know slots, I suggest you learn them first on the Vue.js docs. Scoped slots is an advanced feature in Vue.js that allows you to.

Vue Js Slots Vs Props

  • Syntax to use Vue Slot with v-slot directive along with its shorthand
  • How to use Vue Named Slots with v-slot & examples
  • How to use Vue v-slot for Scoped Slots & examples
  • Vue Dynamic slots example

Related Post: Vue 3 Composition API tutorial with examples


Contents

Vue slots syntax with v-slot directive

With new v-slot directive, we can:
– combine html layers: component tag and scope of the slot.
– combine the slot and the scoped slot in a single directive.

For example, this is old syntax with slot-scope:

This is how we combine ListComponent and template tag:

And this is old named slots syntax:

Now we use new Vue v-slot directive:

You can see that:

– We use <template v-slot:header> to wrap <p> tag instead of <p slot='header'> directly. This is because Vue v-slot can only be used in <component> or <template> html tag. It cannot be used in plain HTML tags (<p> for example).

– We replace slot='content' slot-scope='{data}' with v-slot:content='{data}' by combining slot & slot-scope. With new Vue v-slot directive, all slots are compiled into scoped slots. It improves the performance. Why?

Normal slots are rendered during the parent component’s render cycle. So, if any dependency of a slot changes, both the parent and child components will be re-rendered.

When we use scoped slots, slots are compiled into inline functions and called during the child component’s render cycle. This means:

  • data from a scoped slot are collected by the child component which is re-rendered separately.
  • the changes of parent scope dependency only affect the parent, not the child component. So the child component doesn’t need to update if it uses only scoped slots.

Shorthand for v-slot

# is the shorthand for Vue v-slot directive.
For example, #content stands for v-slot:content.

The code above can be written as:

Remember that when using shorthand, we must always specify the name of the slot after # symbol. We cannot use shorthand like this: #='{item}'.
It must be: #default='{item}' in which, #default is the shorthand for v-slot:default.

In the next parts, we show you some examples that apply new Vue v-slot directive in practice.

Vue v-slot examples with Named Slots

If we want to use multiple slots in one component, Named Slots are useful.
The code below shows BkrCard component template with 3 slots:

  • header
  • title
  • default

Remember that <slot> without name attribute has the name default.

Now look at the parent component which use v-slot directive to specify name for named slots on <template> tag:

The result will be:

If we pass only one named slot, the default value will be shown:

Vue v-slot example with default slot

In the example above, we use <template v-slot:default> for the default slot.

We have other ways to specify html code to be considered as default slot also:

– wrap it in a <template> without Vue v-slot directive:

– do not wrap it in a <template>:

The result are the same for 2 cases:

Vue v-slot examples with Scoped Slots

Props

What we should do when we want a child component to allow parent component access its data?

In this example, categories need to be available to the slot content in the parent. So we bind the categories as an attribute to the <slot> element:

The categories attribute is called slot props.
In the parent scope, Vue v-slot directive can help us get value of the slot props above:

The result will be:

  • Dart
  • Flutter
  • Vue.js

This is shorthand for v-slot:

Vue js slot props car bodies

Vue Dynamic slots example

We can use a JavaScript expression in v-slot directive argument with square brackets:

Now look at the example:

Clicking on the Change button will change the collection value dynamically.
v-slot:[collection]='{categories}' could become:

Vue Js Slot Props Download

  • v-slot:default='{categories}'
  • v-slot:new_categories='{categories}'

This is BkrCategories component with default and new_categories slot name:

The result will be:

Conclusion

We’ve learned almost aspects of new Vue v-slot directive, from v-slot syntax to its handshort, then apply v-slot directive on Named Slot examples to Scoped Slots and Dynamic Slots examples.

Happy learning! See you again!

Further reading