fix(nuxt): improve hmr for pages macros

packages/nuxt/src/pages/page-meta.ts

@@ -13,6 +13,25 @@ export interface PageMetaPluginOptions {
  sourcemap?: boolean
 }
 
+const CODE_EMPTY = `
+const __nuxt_page_meta = {}
+export default __nuxt_page_meta
+`
+
+const CODE_HMR = `
+// Vite
+if (import.meta.hot) {
+ import.meta.hot.accept(mod => {
+ Object.assign(__nuxt_page_meta, mod)
+ })
+}
+// Webpack
+if (import.meta.webpackHot) {
+ import.meta.webpackHot.accept((err) => {
+ if (err) { window.location = window.location.href }
+ })
+}`
+
 export const PageMetaPlugin = createUnplugin((options: PageMetaPluginOptions) => {
  return {
  name: 'nuxt:pages-macros-transform',
@@ -88,7 +107,7 @@ export const PageMetaPlugin = createUnplugin((options: PageMetaPluginOptions) =>
  }
 
  if (!hasMacro && !code.includes('export { default }') && !code.includes('__nuxt_page_meta')) {
- s.overwrite(0, code.length, 'export default {}')
+ s.overwrite(0, code.length, CODE_EMPTY + (options.dev ? CODE_HMR : ''))
  return result()
  }
 
@@ -117,7 +136,7 @@ export const PageMetaPlugin = createUnplugin((options: PageMetaPluginOptions) =>
 
  const meta = node.arguments[0] as Expression & { start: number, end: number }
 
- let contents = `const __nuxt_page_meta = ${code!.slice(meta.start, meta.end) || '{}'}\nexport default __nuxt_page_meta`
+ let contents = `const __nuxt_page_meta = ${code!.slice(meta.start, meta.end) || '{}'}\nexport default __nuxt_page_meta` + (options.dev ? CODE_HMR : '')
 
  function addImport (name: string | false) {
  if (name && importMap.has(name)) {
@@ -147,10 +166,22 @@ export const PageMetaPlugin = createUnplugin((options: PageMetaPluginOptions) =>
  })
 
  if (!s.hasChanged() && !code.includes('__nuxt_page_meta')) {
- s.overwrite(0, code.length, 'export default {}')
+ s.overwrite(0, code.length, CODE_EMPTY + (options.dev ? CODE_HMR : ''))
  }
 
  return result()
+ },
+ vite: {
+ handleHotUpdate: {
+ order: 'pre',
+ handler: ({ modules }) => {
+ // Remove macro file from modules list to prevent HMR overrides
+ const index = modules.findIndex(i => i.id?.includes('?macro=true'))
+ if (index !== -1) {
+ modules.splice(index, 1)
+ }
+ }
+ }
  }
  }
 })