TypeScript

Nuxt is fully typed and provides helpful shortcuts to ensure you have access to accurate type information when you are coding.

Type-checking

By default, Nuxt doesn't check types when you run nuxt dev or nuxt build, for performance reasons.

To enable type-checking at build or development time, install vue-tsc and typescript as development dependency:

npm install --save-dev vue-tsc typescript

Then, run nuxt typecheck command to check your types:

Terminal
npx nuxt typecheck

To enable type-checking at build or development time, you can also use the typescript.typeCheck option in your nuxt.config file:

nuxt.config.ts
export default defineNuxtConfig({
  typescript: {
    typeCheck: true,
  },
})

Auto-generated Types

When you run nuxt dev or nuxt build, Nuxt generates the following files for IDE type support (and type checking):

.nuxt/nuxt.d.ts

This file contains the types of any modules you are using, as well as the key types that Nuxt requires. Your IDE should recognize these types automatically.

Some of the references in the file are to files that are only generated within your buildDir (.nuxt) and therefore for full typings, you will need to run nuxt dev or nuxt build.

.nuxt/tsconfig.json

This file contains the recommended basic TypeScript configuration for your project, including resolved aliases injected by Nuxt or modules you are using, so you can get full type support and path auto-complete for aliases like ~/file or #build/file.

Consider using the imports section of nuxt.config to include directories beyond the default ones. This can be useful for auto-importing types which you're using across your app.

Read more about how to extend this configuration.

Watch a video from Daniel Roe explaining built-in Nuxt aliases.
Nitro also auto-generates types for API routes. Plus, Nuxt also generates types for globally available components and auto-imports from your composables, plus other core functionality.
Keep in mind that all options extended from ./.nuxt/tsconfig.json will be overwritten by the options defined in your tsconfig.json. Overwriting options such as "compilerOptions.paths" with your own configuration will lead TypeScript to not factor in the module resolutions from ./.nuxt/tsconfig.json. This can lead to module resolutions such as #imports not being recognized.

In case you need to extend options provided by ./.nuxt/tsconfig.json further, you can use the alias property within your nuxt.config. Nuxt will pick them up and extend ./.nuxt/tsconfig.json accordingly.

Augmenting Types with Project References

Since the project is divided into multiple type contexts, it's important to augment types within the correct context to ensure they are properly recognized.

For example, if you want to augment types for the app context, the augmentation file should be placed in the app/ directory.

Similarly:

  • For the server context, place the augmentation file in the server/ directory.
  • For types that are shared between the app and server, place the file in the shared/ directory.
Augmenting types outside of these directories will not be recognized by TypeScript.

Strict Checks

TypeScript comes with certain checks to give you more safety and analysis of your program.

Strict checks are enabled by default in Nuxt to give you greater type safety.

If you are currently converting your codebase to TypeScript, you may want to temporarily disable strict checks by setting strict to false in your nuxt.config:

nuxt.config.ts
export default defineNuxtConfig({
  typescript: {
    strict: false,
  },
})