loadConfig makes array type item duplicated.

[higuaifan]

Environment

---

• Operating System: Darwin
• Node Version: v16.14.0
• Nuxt Version: 3.0.0
• Package Manager: pnpm@6.32.3
• Builder: vite
• User Config: extensions, modules
• Runtime Modules: ./modules/markdown
• Build Modules: -

---

Reproduction

I don't think it might be necessary.

Describe the bug

if my nuxt.config.ts like this:

import { defineNuxtConfig } from 'nuxt3';

export default defineNuxtConfig({
  extensions:['.md'],
  modules:[
    './modules/markdown'
  ],
})

in loadNuxtConfig, after run loadConfig,nuxtConfig will like this:

{
  "extensions": [
    ".md",
    ".md"
  ],
  "modules": [
    "./modules/markdown",
    "./modules/markdown"
  ],
}

I believe it is a bug .. or this is a new feature (I don't know much about individual config layers for extending)?

---

in this line used loadConfig ,
https://github.com/nuxt/framework/blob/53fbca77d4b84ac9b8eadd582d7afbbbc5819fa1/packages/kit/src/loader/config.ts#L3
and c12 is upgrade to ^0.2.0 , support individual config layers for extending.
https://github.com/unjs/c12/blob/8808f3793875cf862326163196087cc68c75dae3/src/loader.ts#L99-L125

 const baseLayers = [
    opts.overrides && { config: opts.overrides, configFile: undefined, cwd: undefined },
    { config, configFile: opts.configFile, cwd: opts.cwd },
    opts.rcFile && { config: configRC, configFile: opts.rcFile }
  ].filter(l => l && l.config)

  // Allow extending
  if (opts.extend) {
    await extendConfig(r.config, opts)
    r.layers = [
      ...baseLayers,
      ...r.config._layers
    ]
    delete r.config._layers
    r.config = defu(
      r.config,
      ...r.layers.map(e => e.config)
    ) as T
  }

  // Apply defaults
  if (opts.defaults) {
    r.config = defu(r.config, opts.defaults) as T
  }

  // Return resolved config
  return r

baseLayers includes config and then defu config to r.config...I think the problem might be here..

---

anyway.. It will makes module load twice..

Additional context

No response

Logs

No response

[pi0]

Thanks for the detailed issue @higuaifan. This issue should be resolved by unjs/c12@367cbf8. Can you please try upgrading using npn nuxi upgrade --force?

[higuaifan]

Thanks for the detailed issue @higuaifan. This issue should be resolved by unjs/c12@367cbf8. Can you please try upgrading using npn nuxi upgrade --force?

Yeah! It works ! Thanks for resolve!