feat(nuxt): add watch option and refactor dev server restarting

packages/nuxi/src/commands/dev.ts

@@ -1,7 +1,6 @@
 import type { AddressInfo } from 'node:net'
 import type { RequestListener } from 'node:http'
-import { existsSync, readdirSync } from 'node:fs'
-import { resolve, relative, normalize } from 'pathe'
+import { resolve, relative } from 'pathe'
 import chokidar from 'chokidar'
 import { debounce } from 'perfect-debounce'
 import type { Nuxt } from '@nuxt/schema'
@@ -160,42 +159,11 @@ export default defineNuxtCommand({
     // Watch for config changes
     // TODO: Watcher service, modules, and requireTree
     const dLoad = debounce(load)
-    const watcher = chokidar.watch([rootDir], { ignoreInitial: true, depth: 1 })
-    watcher.on('all', (event, _file) => {
-      if (!currentNuxt) { return }
-      const file = normalize(_file)
-      const buildDir = withTrailingSlash(normalize(currentNuxt.options.buildDir))
-      if (file.startsWith(buildDir)) { return }
-      const relativePath = relative(rootDir, file)
-      if (file.match(/(nuxt\.config\.(js|ts|mjs|cjs)|\.nuxtignore|\.env|\.nuxtrc)$/)) {
-        dLoad(true, `${relativePath} updated`)
-      }
-
-      const isDirChange = ['addDir', 'unlinkDir'].includes(event)
-      const isFileChange = ['add', 'unlink'].includes(event)
-      const pagesDir = resolve(currentNuxt.options.srcDir, currentNuxt.options.dir.pages)
-      const reloadDirs = ['components', 'composables', 'utils'].map(d => resolve(currentNuxt.options.srcDir, d))
-
-      if (isDirChange) {
-        if (reloadDirs.includes(file)) {
-          return dLoad(true, `Directory \`${relativePath}/\` ${event === 'addDir' ? 'created' : 'removed'}`)
-        }
-      }
-
-      if (isFileChange) {
-        if (file.match(/(app|error|app\.config)\.(js|ts|mjs|jsx|tsx|vue)$/)) {
-          return dLoad(true, `\`${relativePath}\` ${event === 'add' ? 'created' : 'removed'}`)
-        }
-      }
-
-      if (file.startsWith(pagesDir)) {
-        const hasPages = existsSync(pagesDir) ? readdirSync(pagesDir).length > 0 : false
-        if (currentNuxt && !currentNuxt.options.pages && hasPages) {
-          return dLoad(true, 'Pages enabled')
-        }
-        if (currentNuxt && currentNuxt.options.pages && !hasPages) {
-          return dLoad(true, 'Pages disabled')
-        }
+    const watcher = chokidar.watch([rootDir], { ignoreInitial: true, depth: 0 })
+    watcher.on('all', (_event, _file) => {
+      const file = relative(rootDir, _file)
+      if (file.match(/^(nuxt\.config\.(js|ts|mjs|cjs)|\.nuxtignore|\.env|\.nuxtrc)$/)) {
+        dLoad(true, `${file} updated`)
       }
     })
 

packages/nuxt/src/components/module.ts

@@ -147,6 +147,17 @@ export default defineNuxtModule<ComponentsOptions>({
       }
     })
 
+    // Restart dev server when component directories are added/removed
+    nuxt.hook('builder:watch', (event, path) => {
+      const isDirChange = ['addDir', 'unlinkDir'].includes(event)
+      const fullPath = resolve(nuxt.options.srcDir, path)
+
+      if (isDirChange && componentDirs.some(dir => dir.path === fullPath)) {
+        console.info(`Directory \`${path}/\` ${event === 'addDir' ? 'created' : 'removed'}`)
+        return nuxt.callHook('restart')
+      }
+    })
+
     // Scan components and add to plugin
     nuxt.hook('app:templates', async () => {
       const newComponents = await scanComponents(componentDirs, nuxt.options.srcDir!)

packages/nuxt/src/core/nuxt.ts

@@ -161,10 +161,6 @@ async function initNuxt (nuxt: Nuxt) {
   // Register user and then ad-hoc modules
   modulesToInstall.push(...nuxt.options.modules, ...nuxt.options._modules)
 
-  nuxt.hooks.hookOnce('builder:watch', (event, path) => {
-    if (watchedPaths.has(path)) { nuxt.callHook('restart', { hard: true }) }
-  })
-
   // Add <NuxtWelcome>
   addComponent({
     name: 'NuxtWelcome',
@@ -268,6 +264,29 @@ async function initNuxt (nuxt: Nuxt) {
 
   await nuxt.callHook('modules:done')
 
+  nuxt.hooks.hook('builder:watch', (event, path) => {
+    // Local module patterns
+    if (watchedPaths.has(path)) {
+      return nuxt.callHook('restart', { hard: true })
+    }
+
+    // User provided patterns
+    for (const pattern of nuxt.options.watch) {
+      if (typeof pattern === 'string') {
+        if (pattern === path) { return nuxt.callHook('restart') }
+        continue
+      }
+      if (pattern.test(path)) { return nuxt.callHook('restart') }
+    }
+
+    // Core Nuxt files: app.vue, error.vue and app.config.ts
+    const isFileChange = ['add', 'unlink'].includes(event)
+    if (isFileChange && path.match(/^(app|error|app\.config)\.(js|ts|mjs|jsx|tsx|vue)$/i)) {
+      console.info(`\`${path}\` ${event === 'add' ? 'created' : 'removed'}`)
+      return nuxt.callHook('restart')
+    }
+  })
+
   // Normalize windows transpile paths added by modules
   nuxt.options.build.transpile = nuxt.options.build.transpile.map(t => typeof t === 'string' ? normalize(t) : t)
 

packages/nuxt/src/imports/module.ts

@@ -61,6 +61,17 @@ export default defineNuxtModule<Partial<ImportsOptions>>({
     await nuxt.callHook('imports:dirs', composablesDirs)
     composablesDirs = composablesDirs.map(dir => normalize(dir))
 
+    // Restart nuxt when composable directories are added/removed
+    nuxt.hook('builder:watch', (event, path) => {
+      const isDirChange = ['addDir', 'unlinkDir'].includes(event)
+      const fullPath = resolve(nuxt.options.srcDir, path)
+
+      if (isDirChange && composablesDirs.includes(fullPath)) {
+        console.info(`Directory \`${path}/\` ${event === 'addDir' ? 'created' : 'removed'}`)
+        return nuxt.callHook('restart')
+      }
+    })
+
     // Support for importing from '#imports'
     addTemplate({
       filename: 'imports.mjs',

packages/nuxt/src/pages/module.ts

@@ -1,6 +1,6 @@
 import { existsSync, readdirSync } from 'node:fs'
 import { defineNuxtModule, addTemplate, addPlugin, addVitePlugin, addWebpackPlugin, findPath, addComponent, updateTemplates } from '@nuxt/kit'
-import { relative, resolve } from 'pathe'
+import { join, relative, resolve } from 'pathe'
 import { genString, genImport, genObjectFromRawEntries } from 'knitwork'
 import escapeRE from 'escape-string-regexp'
 import { joinURL } from 'ufo'
@@ -21,9 +21,10 @@ export default defineNuxtModule({
 
     // Disable module (and use universal router) if pages dir do not exists or user has disabled it
     const isNonEmptyDir = (dir: string) => existsSync(dir) && readdirSync(dir).length
+    const userPreference = nuxt.options.pages
     const isPagesEnabled = () => {
-      if (typeof nuxt.options.pages === 'boolean') {
-        return nuxt.options.pages
+      if (typeof userPreference === 'boolean') {
+        return userPreference
       }
       if (nuxt.options._layers.some(layer => existsSync(resolve(layer.config.srcDir, 'app/router.options.ts')))) {
         return true
@@ -35,6 +36,22 @@ export default defineNuxtModule({
     }
     nuxt.options.pages = isPagesEnabled()
 
+    // Restart Nuxt when pages dir is added or removed
+    const restartPaths = nuxt.options._layers.flatMap(layer => [
+      join(layer.config.srcDir, 'app/router.options.ts'),
+      join(layer.config.srcDir, layer.config.dir?.pages || 'pages')
+    ])
+    nuxt.hooks.hook('builder:watch', (event, path) => {
+      const fullPath = join(nuxt.options.srcDir, path)
+      if (restartPaths.some(path => path === fullPath || fullPath.startsWith(path + '/'))) {
+        const newSetting = isPagesEnabled()
+        if (nuxt.options.pages !== newSetting) {
+          console.info('Pages', newSetting ? 'enabled' : 'disabled')
+          return nuxt.callHook('restart')
+        }
+      }
+    })
+
     if (!nuxt.options.pages) {
       addPlugin(resolve(distDir, 'app/plugins/router'))
       addTemplate({

packages/schema/src/config/common.ts

@@ -345,6 +345,18 @@ export default defineUntypedSchema({
     ].concat(val).filter(Boolean)
   },
 
+  /**
+   * The watch property lets you define patterns that will restart the Nuxt dev server when changed.
+   *
+   * It is an array of strings or regular expressions, which will be matched against the file path
+   * relative to the project `srcDir`.
+   *
+   * @type {Array<string | RegExp>}
+   */
+  watch: {
+    $resolve: val => [].concat(val).filter((b: unknown) => typeof b === 'string' || b instanceof RegExp),
+  },
+
   /**
    * The watchers property lets you overwrite watchers configuration in your `nuxt.config`.
    */