App Config File

Nuxt 3 provides an app.config config file to expose reactive configuration within your application with the ability to update it at runtime within lifecycle or using a nuxt plugin and editing it with HMR (hot-module-replacement).

You can easily provide runtime app configuration using app.config.ts file. It can have either of .ts, .js, or .mjs extensions.

export default defineAppConfig({  foo: 'bar'})

Defining App Config

To expose config and environment variables to the rest of your app, you will need to define configuration in app.config file.

Example:

export default defineAppConfig({  theme: {    primaryColor: '#ababab'  }})

When adding theme to the app.config, Nuxt uses Vite or webpack to bundle the code. We can universally access theme in both server and browser using useAppConfig composable.

const appConfig = useAppConfig()console.log(appConfig.theme)

Manually Typing App Config

Nuxt tries to automatically generate a typescript interface from provided app config.

It is also possible to type app config manually:

declare module '@nuxt/schema' {  interface AppConfigInput {    /** Theme configuration */    theme?: {      /** Primary app color */      primaryColor?: string    }  }}// It is always important to ensure you import/export something when augmenting a typeexport {}