Nuxt/docs/1.getting-started/8.error-handling.md
2024-08-28 22:20:10 +01:00

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---
title: 'Error Handling'
description: 'Learn how to catch and handle errors in Nuxt.'
navigation.icon: i-ph-bug-beetle-duotone
---
Nuxt is a full-stack framework, which means there are several sources of unpreventable user runtime errors that can happen in different contexts:
- Errors during the Vue rendering lifecycle (SSR & CSR)
- Server and client startup errors (SSR + CSR)
- Errors during Nitro server lifecycle ([`server/`](/docs/guide/directory-structure/server) directory)
- Errors downloading JS chunks
::tip
**SSR** stands for **Server-Side Rendering** and **CSR** for **Client-Side Rendering**.
::
## Vue Errors
You can hook into Vue errors using [`onErrorCaptured`](https://vuejs.org/api/composition-api-lifecycle.html#onerrorcaptured).
In addition, Nuxt provides a [`vue:error`](/docs/api/advanced/hooks#app-hooks-runtime) hook that will be called if any errors propagate up to the top level.
If you are using an error reporting framework, you can provide a global handler through [`vueApp.config.errorHandler`](https://vuejs.org/api/application.html#app-config-errorhandler). It will receive all Vue errors, even if they are handled.
```ts twoslash [plugins/error-handler.ts]
export default defineNuxtPlugin((nuxtApp) => {
nuxtApp.vueApp.config.errorHandler = (error, instance, info) => {
// handle error, e.g. report to a service
}
// Also possible
nuxtApp.hook('vue:error', (error, instance, info) => {
// handle error, e.g. report to a service
})
})
```
::note
Note that the `vue:error` hook is based on [`onErrorCaptured`](https://vuejs.org/api/composition-api-lifecycle.html#onerrorcaptured) lifecycle hook.
::
## Startup Errors
Nuxt will call the `app:error` hook if there are any errors in starting your Nuxt application.
This includes:
- running [Nuxt plugins](/docs/guide/directory-structure/plugins)
- processing `app:created` and `app:beforeMount` hooks
- rendering your Vue app to HTML (during SSR)
- mounting the app (on client-side), though you should handle this case with `onErrorCaptured` or with `vue:error`
- processing the `app:mounted` hook
## Nitro Server Errors
You cannot currently define a server-side handler for these errors, but can render an error page, see the [Render an Error Page](#error-page) section.
## Errors with JS Chunks
You might encounter chunk loading errors due to a network connectivity failure or a new deployment (which invalidates your old, hashed JS chunk URLs). Nuxt provides built-in support for handling chunk loading errors by performing a hard reload when a chunk fails to load during route navigation.
You can change this behavior by setting `experimental.emitRouteChunkError` to `false` (to disable hooking into these errors at all) or to `manual` if you want to handle them yourself. If you want to handle chunk loading errors manually, you can check out the [the automatic implementation](https://github.com/nuxt/nuxt/blob/main/packages/nuxt/src/app/plugins/chunk-reload.client.ts) for ideas.
## Error Page
::note
When Nuxt encounters a fatal error (any unhandled error on the server, or an error created with `fatal: true` on the client) it will either render a JSON response (if requested with `Accept: application/json` header) or trigger a full-screen error page.
::
An error may occur during the server lifecycle when:
- processing your Nuxt plugins
- rendering your Vue app into HTML
- a server API route throws an error
It can also occur on the client side when:
- processing your Nuxt plugins
- before mounting the application (`app:beforeMount` hook)
- mounting your app if the error was not handled with `onErrorCaptured` or `vue:error` hook
- the Vue app is initialized and mounted in browser (`app:mounted`).
::read-more{to="/docs/api/advanced/hooks"}
Discover all the Nuxt lifecycle hooks.
::
Customize the default error page by adding `~/error.vue` in the source directory of your application, alongside `app.vue`.
<!-- TODO:twoslash: Twoslash does not support tsconfig paths yet -->
```vue [error.vue]
<script setup lang="ts">
import type { NuxtError } from '#app'
const props = defineProps({
error: Object as () => NuxtError
})
const handleError = () => clearError({ redirect: '/' })
</script>
<template>
<div>
<h2>{{ error.statusCode }}</h2>
<button @click="handleError">Clear errors</button>
</div>
</template>
```
::read-more{to="/docs/guide/directory-structure/error"}
Read more about `error.vue` and its uses.
::
For custom errors we highly recommend to use `onErrorCaptured` composable that can be called in a page/component setup function or `vue:error` runtime nuxt hook that can be configured in a nuxt plugin.
```ts twoslash [plugins/error-handler.ts]
export default defineNuxtPlugin(nuxtApp => {
nuxtApp.hook('vue:error', (err) => {
//
})
})
```
When you are ready to remove the error page, you can call the [`clearError`](/docs/api/utils/clear-error) helper function, which takes an optional path to redirect to (for example, if you want to navigate to a 'safe' page).
::important
Make sure to check before using anything dependent on Nuxt plugins, such as `$route` or `useRouter`, as if a plugin threw an error, then it won't be re-run until you clear the error.
::
::note
Rendering an error page is an entirely separate page load, meaning any registered middleware will run again. You can use [`useError`](#useerror) in middleware to check if an error is being handled.
::
::note
If you are running on Node 16 and you set any cookies when rendering your error page, they will [overwrite cookies previously set](https://github.com/nuxt/nuxt/pull/20585). We recommend using a newer version of Node as Node 16 reached end-of-life in September 2023.
::
## Error Utils
### `useError`
```ts [TS Signature]
function useError (): Ref<Error | { url, statusCode, statusMessage, message, description, data }>
```
This function will return the global Nuxt error that is being handled.
::read-more{to="/docs/api/composables/use-error"}
Read more about `useError` composable.
::
### `createError`
```ts [TS Signature]
function createError (err: string | { cause, data, message, name, stack, statusCode, statusMessage, fatal }): Error
```
Create an error object with additional metadata. You can pass a string to be set as the error `message` or an object containing error properties. It is usable in both the Vue and Server portions of your app, and is meant to be thrown.
If you throw an error created with `createError`:
- on server-side, it will trigger a full-screen error page which you can clear with [`clearError`](#clearerror).
- on client-side, it will throw a non-fatal error for you to handle. If you need to trigger a full-screen error page, then you can do this by setting `fatal: true`.
```vue twoslash [pages/movies/[slug\\].vue]
<script setup lang="ts">
const route = useRoute()
const { data } = await useFetch(`/api/movies/${route.params.slug}`)
if (!data.value) {
throw createError({
statusCode: 404,
statusMessage: 'Page Not Found'
})
}
</script>
```
::read-more{to="/docs/api/utils/create-error"}
Read more about `createError` util.
::
### `showError`
```ts [TS Signature]
function showError (err: string | Error | { statusCode, statusMessage }): Error
```
You can call this function at any point on client-side, or (on server side) directly within middleware, plugins or `setup()` functions. It will trigger a full-screen error page which you can clear with [`clearError`](#clearerror).
It is recommended instead to use `throw createError()`.
::read-more{to="/docs/api/utils/show-error"}
Read more about `showError` util.
::
### `clearError`
```ts [TS Signature]
function clearError (options?: { redirect?: string }): Promise<void>
```
This function will clear the currently handled Nuxt error. It also takes an optional path to redirect to (for example, if you want to navigate to a 'safe' page).
::read-more{to="/docs/api/utils/clear-error"}
Read more about `clearError` util.
::
## Render Error in Component
Nuxt also provides a [`<NuxtErrorBoundary>`](/docs/api/components/nuxt-error-boundary) component that allows you to handle client-side errors within your app, without replacing your entire site with an error page.
This component is responsible for handling errors that occur within its default slot. On client-side, it will prevent the error from bubbling up to the top level, and will render the `#error` slot instead.
The `#error` slot will receive `error` as a prop. (If you set `error = null` it will trigger re-rendering the default slot; you'll need to ensure that the error is fully resolved first or the error slot will just be rendered a second time.)
::tip
If you navigate to another route, the error will be cleared automatically.
::
```vue [pages/index.vue]
<template>
<!-- some content -->
<NuxtErrorBoundary @error="someErrorLogger">
<!-- You use the default slot to render your content -->
<template #error="{ error, clearError }">
You can display the error locally here: {{ error }}
<button @click="clearError">
This will clear the error.
</button>
</template>
</NuxtErrorBoundary>
</template>
```
:link-example{to="/docs/examples/advanced/error-handling"}