Nuxt•3d ago

Odd issues with SSR & hydration mismatch

I have a Nuxt3 project where I use Vue Query. In the .vue file in pages/ I have a hook which fetches data with Vue Query and does onServerPrefetch(suspense), and it works fine, however I have one component inside this page, which has another composable with Vue Query, which also has onServerPrefetch(suspense), but for some reason it's not rendered properly on server and causes a hydration mismatch, however weird thing is that it doesn't show that it would fetch anything in network tab, meaning it does fetch it serverside. The component is a table component using tanstack table, it accepts both json, and an url to fetch the json from. The json server side rendering works fine, but when url is used, the table is initially rendered empty, and on client side renders the rows.

2 Replies

kapa.ai•3d ago

Hi @Hevipelle. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- Based on the information provided in the knowledge sources, I can offer some insights into your issue with SSR and hydration mismatch in your Nuxt 3 project. The problem you're experiencing seems to be related to how data fetching is handled during server-side rendering and client-side hydration. In Nuxt 3, it's crucial to use the appropriate composables for data fetching to avoid hydration mismatches. The main issue here appears to be that you're using Vue Query directly, which may not be fully compatible with Nuxt's SSR and hydration process. Instead, Nuxt provides specific composables for data fetching that are designed to work seamlessly with SSR: 1. useFetch: This is a wrapper around useAsyncData and $fetch, specifically designed for data fetching in Nuxt 3 Docs > Getting-started > Data fetching (https://nuxt.com/docs/getting-started/data-fetching#the-need-for-usefetch-and-useasyncdata). 2. useAsyncData: This composable ensures that if an API call is made on the server, the data is forwarded to the client in the payload, preventing hydration mismatches Docs > Getting-started > Data fetching (https://nuxt.com/docs/getting-started/data-fetching#the-need-for-usefetch-and-useasyncdata). The reason you're seeing a hydration mismatch is likely because the data fetched on the server is not being properly transferred to the client. When using $fetch or other fetching methods directly (as Vue Query might be doing), Nuxt can't ensure that the data is available during client-side hydration, leading to mismatches Docs > Api > Utils > $fetch (https://nuxt.com/docs/api/utils/dollarfetch). To resolve this issue, you should consider refactoring your data fetching logic to use useFetch or useAsyncData. For example:

<script setup>
const { data } = await useFetch('/api/your-endpoint')
</script>

<script setup>
const { data } = await useFetch('/api/your-endpoint')
</script>

This approach ensures that the data is fetched on the server and properly transferred to the client, avoiding hydration mismatches. For your table component that accepts both JSON and a URL, you might need to implement a custom solution using useAsyncData to handle both cases consistently. Here's a basic example:

<script setup>
const props = defineProps(['data', 'url'])

const { data: tableData } = await useAsyncData(
  'tableData',
  () => props.url ? $fetch(props.url) : props.data
)
</script>

<script setup>
const props = defineProps(['data', 'url'])

const { data: tableData } = await useAsyncData(
  'tableData',
  () => props.url ? $fetch(props.url) : props.data
)
</script>

This setup should ensure that whether you're passing JSON directly or fetching from a URL, the data is handled consistently across server and client renders. Remember, when using these Nuxt composables, you don't need to use onServerPrefetch as Nuxt handles the server-side fetching automatically. If you continue to experience issues, you might want to check if there are any specific incompatibilities between Vue Query and Nuxt 3's SSR process. In some cases, you might need to adapt your Vue Query usage to work more harmoniously with Nuxt's data fetching system. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•3d ago

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Odd issues with SSR & hydration mismatch