Nuxt•13mo ago

Issue with Vue 3 + Nuxt 3 useFetch Data Not Displaying in Template

Background

I’m building an app using Nuxt 3 and Vue 3 (Node v20.18.0). I’m running into a fundamental issue with template reactivity when trying to display data fetched with

useFetch

useFetch

. Specifically:

I can log the data from
```
useFetch
```
```
useFetch
```
in
```
<script setup>
```
```
<script setup>
```
, and the data is correct.
However, when binding to the fetched data in the template, the expected reactivity doesn’t occur.
Some solutions work (like wrapping the data in
```
computed
```
```
computed
```
), but they feel unnecessary for something as fundamental as this.

## What I’ve Tried

Debugging Data Reactivity

console.log("Data:", data.value); 
console.log("Title:", data.value.title);

console.log("Data:", data.value); 
console.log("Title:", data.value.title);

These logs always show the correct data and title values.

### 2. Providing Default Values

const { data } = await useFetch('/api', { default: () => ({ title: 'Untitled' }) });

const { data } = await useFetch('/api', { default: () => ({ title: 'Untitled' }) });

Ensures
```
data.value
```
```
data.value
```
is initialized, but this doesn’t fix the template reactivity for
```
data.value.title
```
```
data.value.title
```
.

### 3. Optional Chaining in the Template

<p v-else>Title: {{ data?.value?.title || 'No title available' }}</p>

<p v-else>Title: {{ data?.value?.title || 'No title available' }}</p>

Prevents errors but still doesn’t display the title, even though
```
<pre>{{ data }}</pre>
```
```
<pre>{{ data }}</pre>
```
confirms it exists.

### 4. Using
computed
computed

const computedData = computed(() => data.value);

const computedData = computed(() => data.value);

This works, and the title renders correctly when accessed as
```
computedData.title
```
```
computedData.title
```
.

## Questions

**Why is template reactivity for `data.value.title` failing?**
- This seems like a fundamental part of Vue’s reactivity system, so I’m not sure why I need
```
computed
```
```
computed
```
  for it to work.
**Is this an issue with Nuxt’s `useFetch`?**
- Could Nuxt be optimizing reactivity in a way that breaks expected behavior for deep properties?
**Am I misusing `useFetch`?**
- Is there a better way to fetch data in Nuxt 3 to avoid this issue entirely?
**Is this a known issue?**
- I couldn’t find documentation addressing this specific behavior. Should I file a bug report?

kapa.ai•11/29/24, 5:51 PM

Hi @kāné. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base.

kapa.ai•11/29/24, 5:51 PM

----------------------
Based on the knowledge sources provided, I can address some aspects of your question about the issue with Vue 3 + Nuxt 3 useFetch data not displaying in the template. However, it's important to note that the information available doesn't fully cover all the specifics of your situation.

Regarding why template reactivity for
```
data.value.title
```
```
data.value.title
```
is failing:

The issue you're experiencing might be related to the shallow reactivity of the

data

data

object returned by

useFetch

useFetch

. According to the Nuxt 3 upgrade guide (https://nuxt.com/docs/getting-started/upgrade#shallow-data-reactivity-in-useasyncdata-and-usefetch), the

data

data

object returned from

useFetch

useFetch

is now a rather than a . This means that while the entire

data

data

object is reactive, properties within it may not trigger reactivity when changed.

Regarding whether this is an issue with Nuxt's
```
useFetch
```
```
useFetch
```
:

This behavior is intentional and was introduced as a performance optimization. The upgrade guide (https://nuxt.com/docs/getting-started/upgrade#shallow-data-reactivity-in-useasyncdata-and-usefetch) states that this change brings a significant performance improvement for deeply nested objects and arrays.

About potentially misusing
```
useFetch
```
```
useFetch
```
:

Based on the provided information, it doesn't appear that you're misusing

useFetch

useFetch

. However, if you need deep reactivity, you have a couple of options:

a. You can opt-in to deep reactivity on a per-composable basis:

b. You can change the default behavior project-wide (though this is not recommended):

kapa.ai•11/29/24, 5:51 PM

Regarding whether this is a known issue:

This is not an issue per se, but rather an intentional change in behavior. It's documented in the Nuxt 3 upgrade guide (https://nuxt.com/docs/getting-started/upgrade#shallow-data-reactivity-in-useasyncdata-and-usefetch).

As for your specific implementation, without seeing more of your code, it's difficult to pinpoint exactly why

computed

computed

works while direct access doesn't. However, using

computed

computed

is a valid approach to ensure reactivity when working with complex data structures.

It's worth noting that the Nuxt documentation on data fetching (https://nuxt.com/docs/getting-started/data-fetching#the-need-for-usefetch-and-useasyncdata) explains that

useFetch

useFetch

is designed to solve issues related to double data fetching and hydration. If you're still experiencing unexpected behavior, you might want to double-check your implementation against the examples in the documentation.

If you continue to face issues after trying these approaches, you might want to create a minimal reproduction of your problem and consider reporting it to the Nuxt GitHub repository for further investigation.
----------------------
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----------------------

kapa.ai•11/29/24, 5:51 PM

@308827449213452289 Kapa.ai is still learning and improving, please let me know how I did by reacting below.

Cue•11/29/24, 6:53 PM

When you use data.value in template, you will lose reactivity. Refs are unwrapped in template, so why not just use data.title etc?