Vue provides multiple layers for catching errors: app.config.errorHandler for uncaught errors globally, onErrorCaptured for errors in a component subtree, and try/catch for async operations. A production app should combine all three, plus a user-facing error UI.

app.config.errorHandler (global catch-all)

This is the last line of defense. It catches any unhandled error from components, watchers, lifecycle hooks, and event handlers:

// main.ts
const app = createApp(App)

app.config.errorHandler = (err, instance, info) => {
  console.error('Unhandled error:', err)
  console.error('Component:', instance?.$options?.name || 'unknown')
  console.error('Hook:', info)

  // Send to error tracking service
  reportToSentry(err, { component: instance?.$options?.name, info })
}

Parameter	What it contains
err	The Error object
instance	The component instance that threw (or null)
info	Where the error occurred: 'setup function', 'render function', 'watcher callback', etc. In production builds, info is a shortened numeric code instead of the full string. See the Error Reference for mappings.

onErrorCaptured (component-level boundary)

onErrorCaptured catches errors from any descendant component. It works like an error boundary: you can handle the error locally and prevent it from propagating up.

<!-- components/ErrorBoundary.vue -->
<script setup lang="ts">
const error = ref<Error | null>(null)

onErrorCaptured((err) => {
  error.value = err
  return false // stop propagation — don't reach app.config.errorHandler
})

function retry() {
  error.value = null
}
</script>

<template>
  <div v-if="error" class="error-state">
    <h3>Something went wrong</h3>
    <p>{{ error.message }}</p>
    <button @click="retry">Try again</button>
  </div>
  <slot v-else />
</template>

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Wrap sections of your app that can fail:

<template>
  <AppHeader />
  <ErrorBoundary>
    <RouterView />
  </ErrorBoundary>
  <AppFooter />
</template>

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If a page crashes, the header and footer stay visible. The user sees an error message with a retry button instead of a blank screen.

Return value of onErrorCaptured

Return	Effect
false	Error is captured, stops propagating
true or nothing	Error continues to parent and eventually to app.config.errorHandler

Async error handling

app.config.errorHandler catches errors in async lifecycle hooks and watchers. But $fetch, fetch, or any promise in an event handler needs explicit try/catch:

<script setup>
const error = ref<string | null>(null)
const isLoading = ref(false)

async function submitForm(data: FormData) {
  error.value = null
  isLoading.value = true
  try {
    await $fetch('/api/submit', { method: 'POST', body: data })
    navigateTo('/success')
  } catch (e) {
    error.value = e instanceof Error ? e.message : 'Something went wrong'
  } finally {
    isLoading.value = false
  }
}
</script>

<template>
  <div v-if="error" class="alert-error">{{ error }}</div>
  <form @submit.prevent="submitForm">...</form>
</template>

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Composable for async operations

Extract the try/catch pattern into a reusable composable:

// composables/useAsyncAction.ts
export function useAsyncAction<T>(action: () => Promise<T>) {
  const isLoading = ref(false)
  const error = ref<string | null>(null)

  async function execute() {
    isLoading.value = true
    error.value = null
    try {
      const result = await action()
      return result
    } catch (e) {
      error.value = e instanceof Error ? e.message : 'Unexpected error'
      return null
    } finally {
      isLoading.value = false
    }
  }

  return { execute, isLoading, error }
}

<script setup>
const {
  execute: submit,
  isLoading,
  error
} = useAsyncAction(() =>
  $fetch('/api/submit', { method: 'POST', body: formData })
)
</script>

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Nuxt error handling

Nuxt adds framework-level error handling on top of Vue's:

error.vue catches fatal errors and renders a full-page error screen:

<!-- error.vue -->
<script setup lang="ts">
const props = defineProps<{ error: { statusCode: number; message: string } }>()

function goHome() {
  clearError({ redirect: '/' })
}
</script>

<template>
  <div class="error-page">
    <h1>{{ error.statusCode }}</h1>
    <p>{{ error.message }}</p>
    <button @click="goHome">Go home</button>
  </div>
</template>

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showError / createError for explicit error throwing:

// In a page or middleware
throw createError({ statusCode: 404, statusMessage: 'Page not found' })

NuxtErrorBoundary for scoped error catching:

<template>
  <NuxtErrorBoundary>
    <SomeRiskyComponent />
    <template #error="{ error, clearError }">
      <p>{{ error.message }}</p>
      <button @click="clearError">Retry</button>
    </template>
  </NuxtErrorBoundary>
</template>

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Error handling layers

Try/catch in event handlers (local, explicit)
        ↓ uncaught
onErrorCaptured in ErrorBoundary (component subtree)
        ↓ propagates if not returning false
app.config.errorHandler (global catch-all)
        ↓ in Nuxt
error.vue (fatal page-level errors)

See also: How do you debug SSR requests? · What causes SSR hydration mismatches? · How does the Vue plugin system work?

References

• errorHandler - Vue.js docs
• onErrorCaptured - Vue.js docs
• Error Handling - Nuxt docs