Why Named slots and scoped slots in Vue? - Purpose & Use Cases

The Big Idea

Discover how to make your Vue components truly flexible and dynamic with named and scoped slots!

The Scenario

Imagine building a reusable card component where you want to put different content in the header, body, and footer. You try to hardcode everything inside the card, but then every time you want a different header or footer, you have to rewrite or copy the whole card.

The Problem

Manually changing parts of a component means repeating code or making many versions. It's hard to keep track, easy to make mistakes, and wastes time. You lose flexibility and your code becomes messy and hard to maintain.

The Solution

Named slots let you define multiple placeholders inside a component, so you can fill each part separately. Scoped slots let you pass data from the component to the slot content, making it dynamic and customizable without rewriting the component.

Before vs After

✗ Before

<Card>
  <h1>Title</h1>
  <p>Body text</p>
  <button>Click</button>
</Card>

✓ After

<Card>
  <template #header><h1>Title</h1></template>
  <template #body><p>Body text</p></template>
  <template #footer><button>Click</button></template>
</Card>

What It Enables

You can build flexible, reusable components that let users customize each part easily and even get data from the component to show dynamic content.

Real Life Example

A modal dialog component where you can set a custom title, body message, and buttons, and the buttons can know if the modal is loading or disabled through scoped slots.

Key Takeaways

Named slots let you define multiple customizable areas inside a component.

Scoped slots pass data from the component to the slot content for dynamic rendering.

They make components flexible, reusable, and easier to maintain.

Practice

1. What is the main purpose of named slots in Vue components?

easy

A. To handle component lifecycle hooks

B. To share data from parent to child components

C. To create reactive state inside a component

D. To place different content in specific parts of a component

Solution

1. Step 1: Understand named slots concept

   Named slots allow you to define multiple placeholders inside a component where different content can be inserted.

2. Step 2: Identify the purpose of named slots

   They help organize content by placing it in specific parts of the component template.

3. Final Answer:

   To place different content in specific parts of a component -> Option D

4. Quick Check:

   Named slots = specific content placement [OK]

Hint: Named slots = different content in specific places [OK]

Common Mistakes:

• Confusing named slots with props
• Thinking named slots share data
• Mixing named slots with lifecycle hooks

2. Which of the following is the correct syntax to define a named slot called header inside a Vue component?

easy

A.

B.

C.

D.

Solution

1. Step 1: Recall named slot syntax in Vue

   Named slots are defined using the element with a name attribute.

2. Step 2: Match correct syntax

   The correct syntax is . Other options are invalid or deprecated.

3. Final Answer:

   <slot name="header"></slot> -> Option C

4. Quick Check:

   Named slot syntax = <slot name="..."> [OK]

Hint: Named slots use syntax [OK]

Common Mistakes:

• Using which is deprecated
• Trying to create custom tags like
• Confusing named slots with props

3. Given this parent usage of a scoped slot:

<MyList>
  <template #item="{ item }">
    <li>{{ item.text }}</li>
  </template>
</MyList>

And this child component template:

<ul>
  <slot name="item" :item="listItem"></slot>
</ul>

What will be rendered if listItem is { text: 'Hello' }?

medium

A. Hello

B.

C. {{ item.text }}

D.

Solution

1. Step 1: Understand scoped slot data passing

   The child passes listItem as item to the slot content using :item="listItem".

2. Step 2: Parent uses slot scope to access item.text

   The parent template receives item and renders <li>{{ item.text }}</li>, which becomes <li>Hello</li>.

3. Final Answer:

   <ul><li>Hello</li></ul> -> Option A

4. Quick Check:

   Scoped slot passes data = rendered content [OK]

Hint: Scoped slots pass data object to slot content [OK]

Common Mistakes:

• Ignoring the slot scope and expecting raw slot tags
• Not using the slot props correctly in parent
• Confusing named slots with scoped slots

4. Identify the error in this Vue component usage:

<MyComponent>
  <template slot="footer">Footer Content</template>
</MyComponent>

Assuming MyComponent defines a named slot footer using <slot name="footer">.

medium

A. Missing v-slot directive on template

B. Using deprecated slot attribute instead of #footer shorthand

C. Named slot must be inside MyComponent template, not usage

D. No error, this is correct syntax

Solution

1. Step 1: Check slot syntax in Vue 3

   The slot attribute on template is deprecated in Vue 3.

2. Step 2: Identify correct syntax for named slots

   Use v-slot:footer or shorthand #footer instead of slot="footer".

3. Final Answer:

   Using deprecated slot attribute instead of #footer shorthand -> Option B

4. Quick Check:

   Use v-slot or # for named slots [OK]

Hint: Use v-slot or #, not slot attribute [OK]

Common Mistakes:

• Using old slot attribute syntax
• Confusing slot definition with slot usage
• Thinking no syntax change in Vue 3

5. You want to create a reusable Card component with named slots for header, body, and footer. The body slot should receive a scoped prop info from the component. Which is the correct way to define the Card template?

hard

A.

B.

C.

D.

Solution

1. Step 1: Identify named slots and scoped props

   The body slot must receive the scoped prop info from the component's data.

2. Step 2: Check slot definitions

   Only the body slot has :info='cardInfo' to pass the scoped prop. The others are simple named slots without props.

3. Final Answer:

   Correct template with named slots and scoped prop on body slot -> Option A

4. Quick Check:

   Scoped prop on body slot only [OK]

Hint: Pass scoped props only on slots needing data [OK]

Common Mistakes:

• Passing scoped props on wrong slots
• Missing scoped prop on body slot
• Using default slot instead of named slots