Nuxt•4d ago

May I use code to handle hydration mismatches?

https://github.com/nuxt/nuxt/discussions/30288

GitHub

How to manually handle hydration mismatch? · nuxt nuxt · Discussion...

My application uses Supabase, and because Supabase's JWT refresh is not immediate, it causes hydration mismatches. I found that most hydration mismatches are due to this reason. Can I manually ...

3 Replies

kapa.ai•4d ago

Hi @akaco. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- Yes, you can use code to handle hydration mismatches in Nuxt 3. However, it's important to note that hydration mismatches should generally be avoided by ensuring that the server-rendered content matches the client-side content. That being said, there are some situations where you might need to handle these mismatches programmatically. One approach to handle hydration mismatches is to use the <ClientOnly> component. This component ensures that its content is only rendered on the client-side, which can help avoid hydration mismatches for content that depends on client-side data or browser APIs. Here's an example of how you might use <ClientOnly>:

<template>
  <ClientOnly>
    <div v-if="confirmed">Email confirmed!</div>
  </ClientOnly>
</template>

<template>
  <ClientOnly>
    <div v-if="confirmed">Email confirmed!</div>
  </ClientOnly>
</template>

This approach is mentioned in the Stack Overflow post about handling hydration mismatches (https://stackoverflow.com/questions/77590022). Another technique to handle hydration mismatches is to use useLazyFetch instead of $fetch for data fetching. This can help prevent mismatches caused by data that's only available on the client side:

<script setup>
const { data: result } = await useLazyFetch('/api/confirm', {
  method: 'post',
  body: { key: key },
});

const confirmed = computed(() => !!result.value);
</script>

<script setup>
const { data: result } = await useLazyFetch('/api/confirm', {
  method: 'post',
  body: { key: key },
});

const confirmed = computed(() => !!result.value);
</script>

It's also worth noting that in some cases, you might want to disable server-side rendering for specific routes that are prone to hydration mismatches. You can do this using the routeRules configuration in your nuxt.config.ts:

export default defineNuxtConfig({
  routeRules: {
    '/confirm-key': { ssr: false }
  }
});

export default defineNuxtConfig({
  routeRules: {
    '/confirm-key': { ssr: false }
  }
});

This approach is mentioned in the same Stack Overflow post (https://stackoverflow.com/questions/77590022). Remember, while these techniques can help manage hydration mismatches, it's generally better to address the root cause of the mismatch rather than relying on these workarounds. Always strive to ensure that your server-rendered content matches what will be rendered on the client. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•4d ago

<@1039032964845142027> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

akacoOP•4d ago

My application uses Supabase, and because Supabase's JWT refresh is not immediate, it causes hydration mismatches. I found that most hydration mismatches are due to this reason. Can I manually register an error handler for when a hydration mismatch error occurs?

// plugins/hydration-error-handler.ts
export default defineNuxtPlugin(nuxtApp => {
    nuxtApp.vueApp.config.errorHandler = async (error, instance, info) => {
        console.error('Global error handler:', error, instance, info)

        if (info === 'hydration') {
            console.error('Hydration error detected', error)
            await correctHydrationIssue()
        }
    }
})

async function correctHydrationIssue() {
    const supabase = useSupabaseClient()
    const { error } = await supabase.auth.refreshSession()
    if (error) {
        console.error('Failed to refresh session', error)
        return
    }
}

// plugins/hydration-error-handler.ts
export default defineNuxtPlugin(nuxtApp => {
    nuxtApp.vueApp.config.errorHandler = async (error, instance, info) => {
        console.error('Global error handler:', error, instance, info)

        if (info === 'hydration') {
            console.error('Hydration error detected', error)
            await correctHydrationIssue()
        }
    }
})

async function correctHydrationIssue() {
    const supabase = useSupabaseClient()
    const { error } = await supabase.auth.refreshSession()
    if (error) {
        console.error('Failed to refresh session', error)
        return
    }
}

I found that this doesn't work. I use this user object in many places. If I use client only, it's almost like disabling SSR.

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May I use code to handle hydration mismatches?