Cannot create property 'locales' on string '[object Object]'

[dennisgeerts]

Environment

• Node Version: v22.14.0
• Nuxt Version: 3.15.4
• Nitro Version: 2.10.4
• Package Manager: yarn 1.22.22
• Runtime Modules: @nuxtjs/[email protected]

Reproduction

I could not create a stackblitz that reproduced this error.

i18n: {
    defaultLocale: 'nl-be',
    locales: [
      { code: 'nl-be', name: 'Nederlands (België)', shortName: 'nl', file: 'nl-be.js', dir: 'ltr' },
      { code: 'fr-be', name: 'Français (Belgique)', shortName: 'fr', file: 'fr-be.js', dir: 'ltr' },
      { code: 'en-be', name: 'English (Belgium)', shortName: 'en', file: 'en-be.js', dir: 'ltr' },
    ],
    strategy: 'prefix',
    lazy: true,
    vueI18n: './i18n.config.js',
  },

The i18n.config.js file is in the same root folder as nuxt.config.js:

export default {
  datetimeFormats: {
    'en-be': {
      short: { year: 'numeric', month: 'short', day: 'numeric' },
    },
    'nl-be': {
      short: { year: 'numeric', month: 'short', day: 'numeric' },
    },
    'fr-be': {
      short: { year: 'numeric', month: 'short', day: 'numeric' },
    },
  },
};

The language files are in i18n/locales/nl-be.js, i18n/locales/fr-be.js, i18n/locales/en-be.js. And contain this:

export default defineI18nLocale(async (locale) => {
  return {
    welcome: 'Welkom, Welkom!',
  };
});

Describe the bug

When starting Nuxt i receive the error :
ERROR Cannot start nuxt: Cannot create property 'locales' on string '[object Object]'

I am sure this is related to @nuxtjs/i18n, because if i comment it out in the nuxt.config.js modules, the error disappears and my nuxt application runs.

I tried reducing the sample code above to the absolute minimum but the same error remains.

Additional context

No response

Logs

This is the full stack trace: 

 ERROR  Cannot start nuxt:  Cannot create property 'locales' on string '[object Object]'                                                                                          nuxi  08:11:57  

    at prepareRuntime (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxtjs/i18n/dist/module.mjs:1995:50)
    at setup (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxtjs/i18n/dist/module.mjs:2234:5)
    at async normalizedModule (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxt/kit/dist/index.mjs:2149:17)
    at async installModule (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxt/kit/dist/index.mjs:2427:95)
    at async initNuxt (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/nuxt/dist/shared/nuxt.CrJjphBv.mjs:5339:5)
    at async NuxtDevServer._load (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxt/cli/dist/chunks/dev2.mjs:162:5)
    at async NuxtDevServer.load (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxt/cli/dist/chunks/dev2.mjs:94:7)
    at async NuxtDevServer.init (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxt/cli/dist/chunks/dev2.mjs:89:5)
    at async Object.run (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/@nuxt/cli/dist/chunks/dev-child.mjs:83:5)
    at async runCommand (/C:/Users/dennis/Documents/gad/Projects/gad/frontend/node_modules/citty/dist/index.mjs:316:16)

[BobbieGoede]

I could not create a stackblitz that reproduced this error.

This might be related to using yarn as package manager, there have been a few strange issues exclusive to it recently. A repo with the minimal reproduction would be very helpful to debug this 🙏

The i18n.config.js file is in the same root folder as nuxt.config.js:

This file should be to be in the i18n directory too

[dennisgeerts]

Thanks for your fast reply.
Setting the i18n.config.js file in the i18n folder still gives me the same error, but I missed've missed that from the docs that it belongs there, thanks for the headsup!

I tried transforming the stackblitz from npm to yarn : https://stackblitz.com/edit/bobbiegoede-nuxt-i18n-starter-3fvgnmxg
but i'm not sure if i did it correctly actually.

update: in my own solution i changed everything from Yarn to NPM, but the exact same error still occurs.

[BobbieGoede]

I'm unable to reproduce the issue with that project, I did have to install typescript as a dependency can you give that try?

The module needs to have some additional checks whether typescript is being used or not, currently it relies on typescript whether it is being used or not, to support loading ts files.