Named slots and scoped slots in Vue - Step-by-Step Execution

Concept Flow - Named slots and scoped slots

Parent Component

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Uses Child Component

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Child Component Template

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Named Slot: "header"

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Default Slot

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Named Slot: "footer"

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Scoped Slot: passes data

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Parent fills slots with content

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Parent uses scoped slot data

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Final Rendered Output

The parent component uses the child component and fills named slots with content. Scoped slots pass data from child to parent for dynamic rendering.

Execution Sample

Vue

<ChildComponent>
  <template #header>
    <h1>Title</h1>
  </template>
  <template #default>
    <p>Main content</p>
  </template>
  <template #footer>
    <small>Footer info</small>
  </template>
  <template #scopedSlot="slotProps">
    <p>User: {{ slotProps.user }}</p>
  </template>
</ChildComponent>

Parent component fills named slots 'header', default, 'footer', and uses scoped slot 'scopedSlot' with passed data in the child component.

Execution Table

Step	Action	Slot Name	Passed Data	Rendered Content
1	Parent uses ChildComponent	N/A	N/A	ChildComponent placeholder
2	ChildComponent reads slots	header	N/A	<h1>Title</h1>
3	ChildComponent reads slots	default	N/A	<p>Main content</p>
4	ChildComponent reads slots	footer	N/A	<small>Footer info</small>
5	ChildComponent passes scoped data	scopedSlot	{ user: 'Alice' }	Parent uses user data
6	Parent renders scoped slot content	scopedSlot	{ user: 'Alice' }	<p>User: Alice</p>
7	Final render combines all slots	all	N/A	<h1>Title</h1><p>Main content</p><small>Footer info</small><p>User: Alice</p>

💡 All named and scoped slots filled and rendered, final output complete.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	Final
headerSlotContent	undefined	<h1>Title</h1>	<h1>Title</h1>	<h1>Title</h1>	<h1>Title</h1>	<h1>Title</h1>	<h1>Title</h1>
defaultSlotContent	undefined	undefined	<p>Main content</p>	<p>Main content</p>	<p>Main content</p>	<p>Main content</p>	<p>Main content</p>
footerSlotContent	undefined	undefined	undefined	<small>Footer info</small>	<small>Footer info</small>	<small>Footer info</small>	<small>Footer info</small>
scopedSlotData	undefined	undefined	undefined	undefined	{ user: 'Alice' }	{ user: 'Alice' }	{ user: 'Alice' }
scopedSlotContent	undefined	undefined	undefined	undefined	undefined	<p>User: Alice</p>	<p>User: Alice</p>

Key Moments - 3 Insights

Why does the parent use <template #header> instead of a normal HTML tag?

Because named slots require wrapping content in a <template> with the slot name (#header) so Vue knows which slot to fill, as shown in execution_table step 2.

How does the parent get data from the child in a scoped slot?

The child passes data as an object to the scoped slot (step 5), and the parent accesses it inside the slot template (step 6), enabling dynamic content.

What happens if a named slot is not filled by the parent?

The child renders the default content inside that slot or nothing if none is provided, which is why filling all named slots is important for full output (step 7).

Visual Quiz - 3 Questions

Look at the execution_table at step 5. What data does the child pass to the scoped slot?

A No data passed

B { name: 'Bob' }

C { user: 'Alice' }

D { age: 30 }

💡 Hint

Check the 'Passed Data' column at step 5 in the execution_table.

At which step does the parent render the scoped slot content using the passed data?

A Step 4

B Step 6

C Step 3

D Step 2

💡 Hint

Look for 'Parent renders scoped slot content' in the 'Action' column.

If the parent did not provide content for the 'footer' slot, what would happen?

A The footer slot would render default content or be empty

B An error would occur

C The footer slot would show header content

D The footer slot would be removed from DOM

💡 Hint

Refer to key_moments about what happens if a named slot is not filled.

Concept Snapshot

Named slots let parents fill specific parts of a child component using <template #name>.
Scoped slots pass data from child to parent for dynamic content.
Parent accesses scoped slot data via slot props.
Unfilled named slots render default or nothing.
Use named slots for flexible, reusable components.

Full Transcript

This visual trace shows how Vue named slots and scoped slots work. The parent component uses the child component and fills named slots like 'header', 'default', and 'footer' with content inside <template> tags. The child component reads these slots and renders their content in the right places. Scoped slots allow the child to pass data objects to the parent, which the parent uses to render dynamic content. The execution table tracks each step from slot reading to final rendering. Variable tracking shows how slot content and data change over time. Key moments clarify common confusions like why templates are used for slots and how scoped data is accessed. The quiz tests understanding of slot data passing and rendering steps. The snapshot summarizes the core ideas for quick recall.