Slot basics (default slot) in Svelte - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert default slot content inside the component.

Svelte

<div>
  [1]
</div>

Drag options to blanks, or click blank then click option'

A<slot name="default"></slot>

B<slot></slot>

C<content></content>

D<slot-default></slot-default>

Attempts:

3 left

💡 Hint

Common Mistakes

Using or which are not valid in Svelte.

Adding a name attribute for the default slot which is unnecessary.

The tag is used in Svelte to insert default slot content inside a component.

2fill in blank

medium

Complete the parent component code to pass content into the default slot.

Svelte

<ChildComponent>
  [1]
</ChildComponent>

Drag options to blanks, or click blank then click option'

A<div slot="default">This is slot content</div>

B<slot>This is slot content</slot>

C<template>This is slot content</template>

D<p>This is slot content</p>

Attempts:

3 left

💡 Hint

Common Mistakes

Using slot attributes on elements inside the parent which is only for named slots.

Wrapping content in tags inside the parent which is incorrect.

To pass content into the default slot, simply place the content inside the component tags without any slot attribute.

3fill in blank

hard

Fix the error in the child component to correctly render default slot content.

Svelte

<div>
  [1]
</div>

Drag options to blanks, or click blank then click option'

A{#slot}

B{slot}

C<slot></slot>

D<slot name="default"></slot>

Attempts:

3 left

💡 Hint

Common Mistakes

Using curly braces around slot which is invalid.

Using named slot syntax for default slot.

The correct syntax to render default slot content is using in Svelte.

4fill in blank

hard

Fill both blanks to create a child component that wraps default slot content in a section with a class.

Svelte

<section class=[1]>
  [2]
</section>

Drag options to blanks, or click blank then click option'

A"wrapper"

B<slot></slot>

Cslot

D"content"

Attempts:

3 left

💡 Hint

Common Mistakes

Using class without quotes causing syntax errors.

Not including the tag to render content.

The section should have a class name as a string and include the tag to render default slot content.

5fill in blank

hard

Fill all three blanks to create a parent component passing a paragraph into a child component's default slot with a wrapper class.

Svelte

<ChildComponent class=[1]>
  [2]
</ChildComponent>

<script>
  import ChildComponent from './ChildComponent.svelte';
  let wrapperClass = [3];
</script>

Drag options to blanks, or click blank then click option'

A"main-wrapper"

B<p>Welcome to the slot!</p>

DwrapperClass

Attempts:

3 left

💡 Hint

Common Mistakes

Passing class as a raw string without quotes.

Not importing the child component correctly.

Using slot attributes in the parent for default slot content.

The class attribute is set to a string variable, the paragraph is passed as default slot content, and the variable is defined as a string.

Practice

1. What is the purpose of the default slot in a Svelte component?

easy

A. To display content passed from the parent component if no named slot is used

B. To define a CSS style inside the component

C. To handle component state changes

D. To import external JavaScript files

Solution

1. Step 1: Understand what a slot does

   A slot allows a parent component to pass content into a child component.

2. Step 2: Identify the role of the default slot

   The default slot is the unnamed slot that receives content if no specific slot name is given.

3. Final Answer:

   To display content passed from the parent component if no named slot is used -> Option A

4. Quick Check:

   Default slot = main content placeholder [OK]

Hint: Default slot shows passed content if no slot name given [OK]

Common Mistakes:

• Confusing slots with CSS or state
• Thinking default slot is for styles
• Assuming default slot imports scripts

2. Which of the following is the correct syntax to define a default slot in a Svelte component?

easy

A.

B.

C.

D.

Solution

1. Step 1: Recall slot syntax in Svelte

   The default slot is defined simply with <slot></slot> without a name attribute.

2. Step 2: Check the options for correct syntax

   Only uses <slot></slot> without a name, which is correct for the default slot.

3. Final Answer:

   <slot></slot> -> Option A

4. Quick Check:

   Default slot = <slot></slot> [OK]

Hint: Default slot uses <slot> without name attribute [OK]

Common Mistakes:

• Adding name="default" attribute incorrectly
• Using custom tags like
• Confusing named slots with default slot syntax

3. Given the following Svelte component code, what will be rendered?

<!-- Child.svelte -->
<slot>No content provided</slot>

<!-- Parent.svelte -->
<Child>
  <p>Hello from parent</p>
</Child>

medium

A. No content provided

B. Hello from parent

C. An empty space

D. Error: slot not found

Solution

1. Step 1: Understand default slot behavior

   The <slot> tag shows content passed from the parent if any is provided.

2. Step 2: Check if parent passes content

   The parent passes <p>Hello from parent</p> inside <Child>, so this content replaces the default slot fallback.

3. Final Answer:

   Hello from parent -> Option B

4. Quick Check:

   Parent content replaces default slot fallback [OK]

Hint: Parent content overrides default slot fallback text [OK]

Common Mistakes:

• Assuming fallback text always shows
• Thinking slot content is ignored
• Expecting an error when slot is used

4. Identify the error in this Svelte component using a default slot:

<slot name>Fallback</slot>

medium

A. The fallback content must be outside the slot tag

B. Slots cannot have fallback content

C. The slot tag should not have a name attribute without a value

D. The slot tag must be self-closing

Solution

1. Step 1: Analyze the slot tag attributes

   The slot tag has a name attribute but no value, which is invalid syntax.

2. Step 2: Recall correct slot syntax

   Named slots require a name with a string value, or omit the name attribute for default slot.

3. Final Answer:

   The slot tag should not have a name attribute without a value -> Option C

4. Quick Check:

   Empty name attribute on slot is invalid [OK]

Hint: Name attribute must have a value or be omitted [OK]

Common Mistakes:

• Leaving name attribute empty
• Thinking fallback content is invalid
• Using self-closing slot tags incorrectly

5. You want a Svelte component to show a message passed from the parent, but if no message is given, it should show "Welcome!" by default. Which code correctly uses the default slot to achieve this?

hard

A.

B. Welcome!

C. {message || 'Welcome!'}

D. Welcome!

Solution

1. Step 1: Understand default slot fallback usage

   The default slot shows fallback content if no content is passed from the parent.

2. Step 2: Identify correct fallback syntax

   Using <slot>Welcome!</slot> sets "Welcome!" as fallback text correctly.

3. Step 3: Check other options for errors

   <slot name="default">Welcome!</slot> incorrectly uses name="default" which is unnecessary; C uses invalid expression inside slot; D uses non-existent fallback attribute.

4. Final Answer:

   <slot>Welcome!</slot> -> Option D

5. Quick Check:

   Default slot fallback = content inside <slot> [OK]

Hint: Put fallback text inside <slot> tags for default content [OK]

Common Mistakes:

• Adding name="default" attribute unnecessarily
• Trying to use JavaScript expressions inside slot tags
• Using invalid fallback attributes