Nuxt/docs/6.bridge/1.overview.md

title	description
Overview	Reduce the differences with Nuxt 3 and reduce the burden of migration to Nuxt 3.

::callout If you're starting a fresh Nuxt 3 project, please skip this section and go to Nuxt 3 Installation. ::

::callout{color="amber" icon="i-ph-warning-duotone"} Nuxt Bridge provides identical features to Nuxt 3 (docs) but there are some limitations, notably that useAsyncData and useFetch composables are not available. Please read the rest of this page for details. ::

Bridge is a forward-compatibility layer that allows you to experience many of the new Nuxt 3 features by simply installing and enabling a Nuxt module.

Using Nuxt Bridge, you can make sure your project is (almost) ready for Nuxt 3 and you can gradually proceed with the transition to Nuxt 3.

First Step

Upgrade Nuxt 2

Make sure your dev server (nuxt dev) isn't running, remove any package lock files (package-lock.json and yarn.lock), and install the latest Nuxt 2 version:

- "nuxt": "^2.16.3"
+ "nuxt": "^2.17.3"

Then, reinstall your dependencies:

::code-group

yarn install

npm install

::

::callout Once the installation is complete, make sure both development and production builds are working as expected before proceeding. ::

Install Nuxt Bridge

Install @nuxt/bridge and nuxi as development dependencies:

::code-group

yarn add --dev @nuxt/bridge nuxi

npm install -D @nuxt/bridge nuxi

::

Update nuxt.config

Please make sure to avoid any CommonJS syntax such as module.exports, require or require.resolve in your config file. It will soon be deprecated and unsupported.

You can use static import, dynamic import() and export default instead. Using TypeScript by renaming to nuxt.config.ts is also possible and recommended.

import { defineNuxtConfig } from '@nuxt/bridge'

export default defineNuxtConfig({
  bridge: false
})

Update Commands

The nuxt command should now be changed to the nuxt2 command.

{
  "scripts": {
-   "dev": "nuxt",
+   "dev": "nuxt2",
-   "build": "nuxt build",
+   "build": "nuxt2 build",
-   "start": "nuxt start",
+   "start": "nuxt2 start"
  }
}

Try running nuxt2 once here. You will see that the application works as before.

(If 'bridge' is set to false, your application will operate without any changes as before.)

Upgrade Steps

With Nuxt Bridge, the migration to Nuxt 3 can proceed in steps. The below Upgrade Steps does not need to be done all at once.

• TypeScript

• Migrate Legacy Composition API

• Plugins and Middleware

• Migrate New Composition API

• Meta Tags

• Runtime Config

• Nitro

• Vite

Migrate from CommonJS to ESM

Nuxt 3 natively supports TypeScript and ECMAScript Modules. Please check Native ES Modules for more info and upgrading.