Nuxt data fetching (useFetch, useAsyncData) in Vue - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to fetch data using useFetch in a Nuxt component.

Vue

<script setup>
const { data, error } = [1]('https://api.example.com/items')
</script>

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

AuseAsyncData

BuseFetch

CfetchData

DuseData

Attempts:

3 left

💡 Hint

Common Mistakes

Using useAsyncData instead of useFetch when the question asks specifically for useFetch.

Trying to call a non-existent function like fetchData.

The useFetch composable is used in Nuxt to fetch data reactively in components.

2fill in blank

medium

Complete the code to fetch data using useAsyncData with a key in Nuxt.

Vue

<script setup>
const { data, error } = [1]('users', () => $fetch('/api/users'))
</script>

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

AuseFetch

BfetchAsync

CasyncData

DuseAsyncData

Attempts:

3 left

💡 Hint

Common Mistakes

Using useFetch without a key when the question requires useAsyncData.

Trying to use a non-existent function like fetchAsync.

useAsyncData is used with a key and a fetcher function to load data asynchronously in Nuxt.

3fill in blank

hard

Fix the error in the code by completing the blank with the correct property to access the fetched data.

Vue

<script setup>
const { data } = useFetch('/api/posts')
const posts = data[1]
</script>

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

A.value

B.data

C()

D.fetch

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to access data.data which does not exist.

Calling data() as if it were a function.

In Vue 3 and Nuxt, useFetch returns a ref, so you access the actual data with .value.

4fill in blank

hard

Fill both blanks to create a reactive data fetch with useAsyncData and handle errors.

Vue

<script setup>
const { data, error } = [1]('products', () => $fetch('/api/products'))
if (error[2]) {
  console.error('Failed to load products')
}
</script>

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

AuseAsyncData

BuseFetch

C!== null

D== null

Attempts:

3 left

💡 Hint

Common Mistakes

Using useFetch when a key is required.

Checking if error == null instead of !== null.

useAsyncData fetches data with a key, and checking error !== null detects if an error occurred.

5fill in blank

hard

Fill all three blanks to create a reactive fetch with useFetch, destructure data, and check loading state.

Vue

<script setup>
const { data, error, [1] } = [2]('https://api.example.com/info')
if (![3]) {
  console.log('Loading data...')
}
</script>

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

Apending

BuseFetch

Cloading

DuseAsyncData

Attempts:

3 left

💡 Hint

Common Mistakes

Using loading property which does not exist in useFetch.

Using useAsyncData without a key.

useFetch returns a pending property to indicate loading state. We destructure it and check if loading is ongoing.

Practice

1. What is the main difference between useFetch and useAsyncData in Nuxt?

easy

A. useAsyncData automatically refreshes data, useFetch never does.

B. useAsyncData requires a unique key for caching, useFetch does not.

C. useFetch is only for server-side, useAsyncData is client-side only.

D. useFetch caches data with a key, useAsyncData fetches without caching.

Solution

1. Step 1: Understand useFetch behavior

   useFetch fetches data from a URL quickly but does not require a key for caching.

2. Step 2: Understand useAsyncData behavior

   useAsyncData needs a unique key to cache the fetched data, allowing more control over data reuse.

3. Final Answer:

   useAsyncData requires a unique key for caching, useFetch does not. -> Option B

4. Quick Check:

   Key caching difference = D [OK]

Hint: Remember: useAsyncData needs a key, useFetch is simpler [OK]

Common Mistakes:

• Thinking useFetch caches data with keys
• Confusing client/server usage of both
• Assuming useAsyncData auto-refreshes data

2. Which of the following is the correct syntax to use useAsyncData in a Nuxt component?

easy

A. const { data } = useAsyncData('posts', () => $fetch('/api/posts'))

B. const data = useAsyncData('/api/posts')

C. useAsyncData(() => $fetch('posts'), 'posts')

D. const { data } = useAsyncData(() => fetch('/api/posts'))

Solution

1. Step 1: Check the required parameters for useAsyncData

   The first parameter is a unique key string, the second is a function returning a promise.

2. Step 2: Validate each option's syntax

   const { data } = useAsyncData('posts', () => $fetch('/api/posts')) correctly uses a key 'posts' and a fetch function with $fetch. Others miss the key or use wrong order.

3. Final Answer:

   const { data } = useAsyncData('posts', () => $fetch('/api/posts')) -> Option A

4. Quick Check:

   Key first, fetch function second = A [OK]

Hint: Key string first, fetch function second in useAsyncData [OK]

Common Mistakes:

• Omitting the key parameter
• Swapping parameters order
• Using native fetch instead of $fetch

3. Given this code snippet in a Nuxt component:

const { data, pending } = useFetch('/api/user')

return { data, pending }

What will pending be initially when the component loads?

medium

A. undefined

B. false

C. true

D. null

Solution

1. Step 1: Understand useFetch loading state

   pending is a reactive boolean indicating if the fetch is still in progress.

2. Step 2: Initial value of pending

   When the component loads and fetch starts, pending is true until data arrives.

3. Final Answer:

   true -> Option C

4. Quick Check:

   Loading state pending = true [OK]

Hint: pending is true while fetching data [OK]

Common Mistakes:

• Assuming pending is false initially
• Confusing pending with data presence
• Expecting pending to be null or undefined

4. You wrote this code in a Nuxt component:

const { data } = useAsyncData(() => $fetch('/api/items'))

But the data never loads. What is the likely problem?

medium

A. Using $fetch instead of native fetch.

B. Returning data directly instead of inside a function.

C. Not awaiting the useAsyncData call.

D. Missing a unique key as the first argument to useAsyncData.

Solution

1. Step 1: Check useAsyncData parameters

   useAsyncData requires a unique key string as the first argument for caching.

2. Step 2: Identify missing key issue

   Omitting the key causes the fetch not to run properly or cache data, so data never loads.

3. Final Answer:

   Missing a unique key as the first argument to useAsyncData. -> Option D

4. Quick Check:

   Key missing in useAsyncData = B [OK]

Hint: Always provide a key string first in useAsyncData [OK]

Common Mistakes:

• Skipping the key argument
• Confusing $fetch with fetch as cause
• Expecting useAsyncData to be awaited

5. You want to fetch user data and posts in a Nuxt page using useAsyncData. You want posts to refresh every time the user ID changes. Which approach correctly achieves this?

hard

A. Use useAsyncData with a key including the user ID, e.g., useAsyncData(`posts-${userId}`, () => $fetch(`/api/posts?user=${userId}`)).

B. Use useAsyncData with a fixed key 'posts' and rely on automatic refresh.

C. Use useFetch instead of useAsyncData because it auto-refreshes on param change.

D. Call useAsyncData without a key and manually watch userId to refetch.

Solution

1. Step 1: Understand caching with keys in useAsyncData

   Keys uniquely identify cached data. Changing the key triggers a new fetch.

2. Step 2: Use dynamic key with user ID

   Including userId in the key string ensures posts refetch when userId changes.

3. Step 3: Evaluate other options

   Fixed keys won't refresh; useFetch doesn't auto-refresh on param change; manual watch is more complex.

4. Final Answer:

   Use useAsyncData with a key including the user ID, e.g., useAsyncData(`posts-${userId}`, () => $fetch(`/api/posts?user=${userId}`)). -> Option A

5. Quick Check:

   Dynamic key triggers refetch = C [OK]

Hint: Include changing params in key string for refetch [OK]

Common Mistakes:

• Using fixed keys expecting auto-refresh
• Assuming useFetch auto-refreshes on param change
• Skipping key causes no caching or refetch