packages/schema/src/config/app.ts

import { defineUntypedSchema } from 'untyped'
import { defu } from 'defu'
import type { AppHeadMetaObject } from '../types/head'

export default defineUntypedSchema({
  /**
   * Vue.js config
   */
  vue: {
    /**
     * Options for the Vue compiler that will be passed at build time.
     * @see [documentation](https://vuejs.org/api/application.html#app-config-compileroptions)
     * @type {typeof import('@vue/compiler-core').CompilerOptions}
     */
    compilerOptions: {},
  },

  /**
   * Nuxt App configuration.
   */
  app: {
    /**
     * The base path of your Nuxt application.
     *
     * This can be set at runtime by setting the NUXT_APP_BASE_URL environment variable.
     * @example
     * ```bash
     * NUXT_APP_BASE_URL=/prefix/ node .output/server/index.mjs
     * ```
     */
    baseURL: {
      $resolve: async (val) => val || process.env.NUXT_APP_BASE_URL || '/',
    },

    /** The folder name for the built site assets, relative to `baseURL` (or `cdnURL` if set). This is set at build time and should not be customized at runtime. */
    buildAssetsDir: {
      $resolve: async (val) => val || process.env.NUXT_APP_BUILD_ASSETS_DIR || '/_nuxt/',
    },

    /**
     * An absolute URL to serve the public folder from (production-only).
     *
     * This can be set to a different value at runtime by setting the `NUXT_APP_CDN_URL` environment variable.
     * @example
     * ```bash
     * NUXT_APP_CDN_URL=https://mycdn.org/ node .output/server/index.mjs
     * ```
     */
    cdnURL: {
      $resolve: async (val, get) => (await get('dev')) ? '' : (process.env.NUXT_APP_CDN_URL ?? val) || ''
    },

    /**
     * Set default configuration for `<head>` on every page.
     *
     * @example
     * ```js
     * app: {
     *   head: {
     *     meta: [
     *       // <meta name="viewport" content="width=device-width, initial-scale=1">
     *       { name: 'viewport', content: 'width=device-width, initial-scale=1' }
     *     ],
     *     script: [
     *       // <script src="https://myawesome-lib.js"></script>
     *       { src: 'https://awesome-lib.js' }
     *     ],
     *     link: [
     *       // <link rel="stylesheet" href="https://myawesome-lib.css">
     *       { rel: 'stylesheet', href: 'https://awesome-lib.css' }
     *     ],
     *     // please note that this is an area that is likely to change
     *     style: [
     *       // <style type="text/css">:root { color: red }</style>
     *       { children: ':root { color: red }', type: 'text/css' }
     *     ],
     *     noscript: [
     *       // <noscript>JavaScript is required</noscript>
     *       { children: 'JavaScript is required' }
     *     ]
     *   }
     * }
     * ```
     * @type {typeof import('../src/types/config').NuxtAppConfig['head']}
     */
    head: {
      $resolve: async (val, get) => {
        const resolved: Required<AppHeadMetaObject> = defu(val, await get('meta'), {
          meta: [],
          link: [],
          style: [],
          script: [],
          noscript: []
        })

        // provides default charset and viewport if not set
        if (!resolved.meta.find(m => m.charset)?.charset) {
          resolved.meta.unshift({ charset: resolved.charset || 'utf-8' })
        }
        if (!resolved.meta.find(m => m.name === 'viewport')?.content) {
          resolved.meta.unshift({ name: 'viewport', content: resolved.viewport || 'width=device-width, initial-scale=1' })
        }

        resolved.meta = resolved.meta.filter(Boolean)
        resolved.link = resolved.link.filter(Boolean)
        resolved.style = resolved.style.filter(Boolean)
        resolved.script = resolved.script.filter(Boolean)
        resolved.noscript = resolved.noscript.filter(Boolean)

        return resolved
      }
    },

    /**
     * Default values for layout transitions.
     *
     * This can be overridden with `definePageMeta` on an individual page.
     * Only JSON-serializable values are allowed.
     *
     * @see https://vuejs.org/api/built-in-components.html#transition
     * @type {typeof import('../src/types/config').NuxtAppConfig['layoutTransition']}
     */
    layoutTransition: false,

    /**
     * Default values for page transitions.
     *
     * This can be overridden with `definePageMeta` on an individual page.
     * Only JSON-serializable values are allowed.
     *
     * @see https://vuejs.org/api/built-in-components.html#transition
     * @type {typeof import('../src/types/config').NuxtAppConfig['pageTransition']}
     */
    pageTransition: false,

    /**
     * Default values for KeepAlive configuration between pages.
     *
     * This can be overridden with `definePageMeta` on an individual page.
     * Only JSON-serializable values are allowed.
     *
     * @see https://vuejs.org/api/built-in-components.html#keepalive
     * @type {typeof import('../src/types/config').NuxtAppConfig['keepalive']}
     */
    keepalive: false,

    /**
     * Customize Nuxt root element id.
     */
    rootId: '__nuxt',

    /**
     * Customize Nuxt root element tag.
     *
     */
    rootTag: 'div',
  },

  /**
   * An array of nuxt app plugins.
   *
   * Each plugin can be a string (which can be an absolute or relative path to a file).
   * If it ends with `.client` or `.server` then it will be automatically loaded only
   * in the appropriate context.
   *
   * It can also be an object with `src` and `mode` keys.
   *
   * @note Plugins are also auto-registered from the `~/plugins` directory
   * and these plugins do not need to be listed in `nuxt.config` unless you
   * need to customize their order. All plugins are deduplicated by their src path.
   *
   * @see https://nuxt.com/docs/guide/directory-structure/plugins
   *
   * @example
   * ```js
   * plugins: [
   *   '~/plugins/foo.client.js', // only in client side
   *   '~/plugins/bar.server.js', // only in server side
   *   '~/plugins/baz.js', // both client & server
   *   { src: '~/plugins/both-sides.js' },
   *   { src: '~/plugins/client-only.js', mode: 'client' }, // only on client side
   *   { src: '~/plugins/server-only.js', mode: 'server' } // only on server side
   * ]
   * ```
   * @type {(typeof import('../src/types/nuxt').NuxtPlugin | string)[]}
   */
  plugins: [],

  /**
   * You can define the CSS files/modules/libraries you want to set globally
   * (included in every page).
   *
   * Nuxt will automatically guess the file type by its extension and use the
   * appropriate pre-processor. You will still need to install the required
   * loader if you need to use them.
   *
   * @example
   * ```js
   * css: [
   *   // Load a Node.js module directly (here it's a Sass file).
   *   'bulma',
   *   // CSS file in the project
   *   '@/assets/css/main.css',
   *   // SCSS file in the project
   *   '@/assets/css/main.scss'
   * ]
   * ```
   * @type {string[]}
   */
  css: {
    $resolve: val => (val ?? []).map((c: any) => c.src || c)
  }
})