#useLazyFetch not working?

13 messages · Page 1 of 1 (latest)

bronze totemBOT
#

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

#

You're experiencing a common confusion with useLazyFetch in Nuxt 3. Let me explain what's happening.

When you use useLazyFetch or useFetch with lazy: true, it doesn't necessarily show a loading state when refreshing the page. The "lazy" option primarily affects client-side navigation behavior, not full page refreshes.

Here's what's happening:

  1. When you refresh the page, the data fetching happens on the server side before the page is sent to the client. This is why you don't see the loading state - the data is already available when the page renders.

  2. The "lazy" option is mainly useful for client-side navigation (like when clicking NuxtLink), where it allows navigation to happen immediately without waiting for data to load, showing your loading state while data is being fetched.

As the documentation states:

Awaiting useLazyFetch in this mode only ensures the call is initialized. On client-side navigation, data may not be immediately available, and you should make sure to handle the pending state in your app. Nuxt Documentation

If you want to see the loading state on a page refresh, you would need to use server: false option to prevent server-side fetching:

const { data, status, error, refresh } = await useLazyFetch(
  "<https://restfultest.netlify.app/api/posts",>
  { server: false }
);

This way, the data will only be fetched on the client side after the page loads, and you'll see your loading state.

For more information on client-only fetching, you can check the Nuxt documentation on data fetching.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

#

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

frosty pond
#

ok I suppose I am sleepy

#

@bronze totem getting hydration warnings when doing this: <script lang="ts" setup>
const { data, status, error, refresh } = await useLazyFetch(
"https://restfultest.netlify.app/api/posts",
{
server: false,
}
);
</script>

<template>
<div>
<NuxtLink to="/test">Test</NuxtLink>
<h1>Fetch</h1>
<p>Status: {{ status }}</p>
<div v-if="status === 'pending'">
<p>Loading...</p>
</div>
<div v-else-if="status === 'success'">
<p>Data: {{ data }}</p>
</div>
<div v-else>
<p>Error</p>
<p>{{ error }}</p>
</div>
</div>
</template>

bronze totemBOT
#

Let me check the knowledge base for you again. One moment! :books:

#

You're encountering hydration warnings because of a mismatch between what's rendered on the server versus what's rendered on the client when using useLazyFetch with server: false.

Here's what's happening:

  1. On the server, when server: false is set, the data isn't fetched, and the status is set to 'idle' (not 'pending').
  2. On the client after hydration, the fetch request begins and the status changes to 'pending'.
  3. This difference in status between server and client causes the hydration mismatch.

As explained in the Nuxt documentation:

If you have not fetched data on the server (for example, with server: false), then the data will not be fetched until hydration completes. This means even if you await useFetch on client-side, data will remain null within <script setup>. Nuxt Documentation

To fix this issue, you have a few options:

  1. Use client-only components for the parts that depend on the fetched data:
<template>
  <div>
    <NuxtLink to="/test">Test</NuxtLink>
    <h1>Fetch</h1>
    <p>Status: {{ status }}</p>
    <ClientOnly>
      <div v-if="status === 'pending'">
        <p>Loading...</p>
      </div>
      <div v-else-if="status === 'success'">
        <p>Data: {{ data }}</p>
      </div>
      <div v-else>
        <p>Error</p>
        <p>{{ error }}</p>
      </div>
    </ClientOnly>
  </div>
</template>
  1. Check for the 'idle' status as well:
<template>
  <div>
    <NuxtLink to="/test">Test</NuxtLink>
    <h1>Fetch</h1>
    <p>Status: {{ status }}</p>
    <div v-if="status === 'pending' || status === 'idle'">
      <p>Loading...</p>
    </div>
    <div v-else-if="status === 'success'">
      <p>Data: {{ data }}</p>
    </div>
    <div v-else>
      <p>Error</p>
      <p>{{ error }}</p>
    </div>
  </div>
</template>
#
  1. Make the entire page client-only by setting the route rule in your nuxt.config.ts:
export default defineNuxtConfig({
  routeRules: {
    '/your-page-path': { ssr: false }
  }
});

This approach is similar to the solution mentioned in the Stack Overflow post about handling hydration mismatches in Nuxt 3 Stack Overflow.

Hydration mismatches occur when the DOM structure rendered on the server differs from what's rendered on the client during hydration. With Vue 3.4 and Nuxt 3.9+, these errors are more detailed and easier to debug, but the fundamental solution remains ensuring consistency between server and client rendering.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

#

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

frosty pond
#

@bronze totem <script lang="ts" setup>
const { data, status, error, refresh } = await useLazyFetch(
"https://restfultest.netlify.app/api/posts",
{
server: false,
}
);
</script>

<template>
<div>
<NuxtLink to="/test">Test</NuxtLink>
<h1>Fetch</h1>
<p>Status: {{ status }}</p>
<div v-if="status === 'pending'">
<p>Loading...</p>
</div>
<div v-else-if="status === 'success'">
<p>Data: {{ data }}</p>
</div>
<div v-else-if="status === 'error'">
<p>Error</p>
<p>{{ error }}</p>
</div>
<div v-else-if="status === 'idle'">
<p>Idle</p>
</div>
</div>
</template>
this still gives hydration warnings

bronze totemBOT
#

Let me check the knowledge base for you again. One moment! :books:

#

I see you're still experiencing hydration warnings even after handling all the possible status values in your template. This is a common issue when using useLazyFetch with server: false.

The core problem is that when you use await with useLazyFetch and server: false, there's still a fundamental mismatch between server and client rendering. On the server, the status is 'idle', but as soon as hydration begins on the client, the fetch starts and the status changes to 'pending'.

Here are some approaches to resolve this issue:

  1. Use useNuxtApp().isHydrating to check if hydration is in progress:
<script lang="ts" setup>
const nuxtApp = useNuxtApp()
const { data, status, error, refresh } = await useLazyFetch(
  "<https://restfultest.netlify.app/api/posts",>
  {
    server: false,
    immediate: !nuxtApp.isHydrating // Only start fetch after hydration
  }
);
</script>
  1. Use ClientOnly component to wrap the parts that depend on the fetched data:
<template>
  <div>
    <NuxtLink to="/test">Test</NuxtLink>
    <h1>Fetch</h1>
    <ClientOnly>
      <p>Status: {{ status }}</p>
      <div v-if="status === 'pending'">
        <p>Loading...</p>
      </div>
      <div v-else-if="status === 'success'">
        <p>Data: {{ data }}</p>
      </div>
      <div v-else-if="status === 'error'">
        <p>Error</p>
        <p>{{ error }}</p>
      </div>
      <div v-else-if="status === 'idle'">
        <p>Idle</p>
      </div>
    </ClientOnly>
  </div>
</template>
  1. Make the entire page client-side only by setting a route rule in your nuxt.config.ts:
export default defineNuxtConfig({
  routeRules: {
    '/your-page-path': { ssr: false }
  }
});
#

This approach is recommended in the Stack Overflow post about handling hydration mismatches and is often the simplest solution.

The fundamental issue is that when you mix server-side rendering with client-only data fetching, you're creating conditions for hydration mismatches. Either make the component fully client-side or ensure the data fetching behavior is consistent between server and client.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: