Else and else-if blocks in Svelte - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What will this Svelte component display?

Consider this Svelte code snippet:

<script>
  let score = 75;
</script>

{#if score >= 90}
  <p>Excellent</p>
{:else if score >= 60}
  <p>Good</p>
{:else}
  <p>Needs Improvement</p>
{/if}

What text will appear when this component renders?

Svelte

<script>
  let score = 75;
</script>

{#if score >= 90}
  <p>Excellent</p>
{:else if score >= 60}
  <p>Good</p>
{:else}
  <p>Needs Improvement</p>
{/if}

A Good

B Needs Improvement

C Excellent

D No text will appear

💡 Hint

Check the conditions in order and see which one matches the score value.

The score is 75, which is not >= 90, so the first block is skipped. The else-if checks if score >= 60, which is true, so 'Good' is displayed.

📝 Syntax

intermediate

Identify the syntax error in this Svelte conditional block

Which option correctly fixes the syntax error in this Svelte code?

{#if loggedIn}
  <p>Welcome back!</p>
{:else if}
  <p>Please log in.</p>
{/if}

Svelte

{#if loggedIn}
  <p>Welcome back!</p>
{:else if}
  <p>Please log in.</p>
{/if}

A {:else if loggedIn === false}

B {:else}

C {:else if !loggedIn}

D {:else if}

💡 Hint

The else-if block requires a condition; else block does not.

The else-if block must have a condition. Here, no condition is given, so it should be replaced with {:else} to handle the fallback case.

🔧 Debug

advanced

Why does this Svelte else-if block never run?

Given this code:

{#if value > 10}
  <p>Greater than 10</p>
{:else if value > 5}
  <p>Greater than 5</p>
{:else}
  <p>5 or less</p>
{/if}

If value is 12, why does the 'Greater than 5' block never show?

Svelte

{#if value > 10}
  <p>Greater than 10</p>
{:else if value > 5}
  <p>Greater than 5</p>
{:else}
  <p>5 or less</p>
{/if}

A Because else-if blocks are not supported in Svelte

B Because else-if conditions must be checked before if

C Because value 12 is not greater than 5

D Because the first if condition is true, so else-if is skipped

💡 Hint

Remember how if-else chains work: once a condition matches, the rest are ignored.

When value is 12, the first if condition (value > 10) is true, so Svelte renders that block and skips the else-if and else blocks.

❓ state_output

advanced

What text appears after clicking the button twice?

This Svelte component toggles a number and shows different text:

<script>
  let count = 0;
</script>

{#if count === 0}
  <p>Zero</p>
{:else if count === 1}
  <p>One</p>
{:else}
  <p>Many</p>
{/if}

<button on:click={() => count++}>Add</button>

What text is shown after clicking the button two times?

Svelte

<script>
  let count = 0;
</script>

{#if count === 0}
  <p>Zero</p>
{:else if count === 1}
  <p>One</p>
{:else}
  <p>Many</p>
{/if}

<button on:click={() => count++}>Add</button>

A Zero

B No text

C Many

D One

💡 Hint

Count how many times the button is clicked and check the conditions.

After two clicks, count is 2, which matches the else block condition, so 'Many' is displayed.

🧠 Conceptual

expert

How does Svelte handle multiple else-if blocks internally?

In Svelte, when you write multiple {:else if} blocks in a conditional, how does Svelte process them when rendering?

A Svelte compiles them into nested if-else JavaScript statements, checking conditions in order

B Svelte runs all else-if conditions in parallel and renders all matching blocks

C Svelte converts else-if blocks into separate components rendered conditionally

D Svelte ignores else-if blocks and only uses the first if and else blocks

💡 Hint

Think about how if-else chains work in JavaScript and how Svelte compiles templates.

Svelte compiles the template into JavaScript code that uses nested if-else statements, evaluating conditions in order and rendering only the first matching block.

Practice

1. In Svelte, which block is used to check a second condition if the first {#if} condition is false?

easy

A. {:else}

B. {#each}

C. {:else if}

D. {#await}

Solution

1. Step 1: Understand the purpose of {#if} and {:else if}

   The {#if} block checks the first condition. If it is false, {:else if} allows checking another condition.

2. Step 2: Identify the correct block for a second condition

   {:else if} is specifically designed to check additional conditions after the first fails.

3. Final Answer:

   {:else if} -> Option C

4. Quick Check:

   Second condition check = {:else if} [OK]

Hint: Use {:else if} to test another condition after {#if} fails [OK]

Common Mistakes:

• Using {:else} to check a condition instead of fallback
• Confusing {#each} with conditional blocks
• Trying to use {#await} for conditions

2. Which of the following is the correct syntax for an else-if block in Svelte?

easy

A. {:elseif condition}

B. {:else if condition}

C. {:else-if condition}

D. {:else if (condition)}

Solution

1. Step 1: Recall Svelte syntax for else-if

   Svelte uses {:else if} followed by the condition without parentheses.

2. Step 2: Compare options to correct syntax

   {:else if condition} matches the correct syntax exactly: {:else if condition}

3. Final Answer:

   {:else if condition} -> Option B

4. Quick Check:

   Correct else-if syntax = {:else if condition} [OK]

Hint: Remember: space between else and if, no parentheses [OK]

Common Mistakes:

• Writing {:elseif} as one word
• Adding parentheses around condition
• Using hyphen in else-if

3. What will be rendered by this Svelte code?

{`\n{#if score >= 90}\n  
Excellent
\n{:else if score >= 60}\n  
Good
\n{:else}\n  
Try again
\n{/if}`}

medium

A. Good

B. Try again

C. Excellent

D. No output

Solution

1. Step 1: Evaluate the first condition

   score is 75, which is not >= 90, so the first {#if} block is false.

2. Step 2: Evaluate the else-if condition

   score is 75, which is >= 60, so {:else if} block is true and renders <p>Good</p>.

3. Final Answer:

   <p>Good</p> -> Option A

4. Quick Check:

   score 75 triggers else-if block = Good [OK]

Hint: Check conditions top-down; first true block renders [OK]

Common Mistakes:

• Assuming all blocks render instead of only one
• Misreading the score value
• Confusing else-if with else

4. Identify the error in this Svelte code snippet:

{`{#if isActive}\n  
Active
\n{:else if}\n  
Inactive
\n{/if}`}

medium

A. Missing condition after {:else if}

B. Incorrect closing tag {/if}

C. Cannot use {:else if} after {#if}

D. Missing colon before else

Solution

1. Step 1: Check {:else if} syntax

   The {:else if} block requires a condition to follow it, but none is provided here.

2. Step 2: Confirm other parts are correct

   The {#if} and {/if} tags are correctly placed, and {:else if} is allowed after {#if}.

3. Final Answer:

   Missing condition after {:else if} -> Option A

4. Quick Check:

   {:else if} needs a condition [OK]

Hint: Always add a condition after {:else if} [OK]

Common Mistakes:

• Leaving {:else if} without condition
• Confusing {:else} with {:else if}
• Misplacing {/if} tag

5. Given this Svelte code:

{`\n{#if status === 'loading'}\n  
Loading...
\n{:else if status === 'success'}\n  
Data loaded
\n{:else if status === 'error'}\n  
Error occurred
\n{:else}\n  
Idle
\n{/if}`}

What will be displayed if status is an empty string?

hard

A. Loading...

B. Data loaded

C. Error occurred

D. Idle

Solution

1. Step 1: Check each condition against empty string

   status is '', so none of the conditions 'loading', 'success', or 'error' match.

2. Step 2: Use {:else} block as fallback

   Since no conditions match, the {:else} block runs, rendering <p>Idle</p>.

3. Final Answer:

   <p>Idle</p> -> Option D

4. Quick Check:

   Empty string triggers else block = Idle [OK]

Hint: If no conditions match, {:else} block runs [OK]

Common Mistakes:

• Assuming empty string matches a condition
• Forgetting {:else} fallback
• Mixing up else-if and else blocks