Slot fallback content in Svelte - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What will this Svelte component render if no slot content is provided?

Consider this Svelte component:

<slot>Default fallback</slot>

What will be displayed if the component is used without any slot content?

Svelte

<slot>Default fallback</slot>

A An error will occur because the slot is empty.

B Nothing will be rendered because no slot content is provided.

C The component will render an empty space with no text.

D The text 'Default fallback' will be rendered.

💡 Hint

Think about what fallback content inside a <slot> tag does when no content is passed.

In Svelte, if no content is passed to a slot, the fallback content inside the <slot> tag is rendered instead.

❓ state_output

intermediate

What is the output when slot content is provided?

Given this Svelte component:

<slot>Fallback</slot>

And it is used like this:

<MyComponent>Hello</MyComponent>

What will be rendered inside MyComponent?

Svelte

<slot>Fallback</slot>

A Nothing will be rendered.

B Both 'Hello' and 'Fallback' will be rendered.

C The text 'Hello' will be rendered.

D The text 'Fallback' will be rendered.

💡 Hint

Remember that slot content overrides fallback content.

When slot content is provided, it replaces the fallback content inside the <slot> tag.

📝 Syntax

advanced

Which option correctly uses fallback content in a named slot?

Which of the following Svelte code snippets correctly defines a named slot with fallback content?

A <slot name="header">Default Header</slot>

B <slot name='header' Default Header></slot>

C <slot name=header>Default Header</slot>

D <slot name="header" Default Header></slot>

💡 Hint

Check the correct syntax for named slots and fallback content.

The correct syntax uses quotes around the name attribute and places fallback content between the opening and closing <slot> tags.

🔧 Debug

advanced

Why does this fallback content not appear?

Given this Svelte component:

<slot>Fallback Content</slot>

And it is used like this:

<MyComponent><div></div></MyComponent>

The fallback content does not appear. Why?

Svelte

<slot>Fallback Content</slot>

A Because an empty &lt;div&gt; counts as slot content, so fallback is ignored.

B Because fallback content only shows if slot content is a string.

C Because fallback content must be inside a named slot to show.

D Because the slot tag is missing a closing tag.

💡 Hint

Think about what counts as slot content in Svelte.

Any content inside the slot, even an empty element, replaces the fallback content.

🧠 Conceptual

expert

How does Svelte handle multiple fallback contents in nested slots?

Consider a Svelte component with nested slots, each having fallback content. If the outer slot receives no content but the inner slot does, what will be rendered?

Svelte

<!-- Outer.svelte -->
<slot>
  <Inner />
</slot>

<!-- Inner.svelte -->
<slot>Inner fallback</slot>

A Only Outer fallback content is rendered, Inner is ignored.

B The Inner component renders its slot content or fallback, and Outer renders Inner as fallback.

C An error occurs because nested slots cannot have fallback content.

D Nothing is rendered because Outer slot has no content.

💡 Hint

Think about how fallback content works recursively in nested slots.

If Outer slot has no content, it renders its fallback which includes Inner. Inner then renders its own slot content or fallback.