fix: support localePath with path input and customized routes

src/templates/plugin.routing.js

@@ -49,7 +49,7 @@ function localeRoute (route, locale) {
     }
   }
 
-  const localizedRoute = Object.assign({}, route)
+  let localizedRoute = Object.assign({}, route)
 
   if (route.path && !route.name) {
     const isDefaultLocale = locale === defaultLocale
@@ -61,10 +61,22 @@ function localeRoute (route, locale) {
         !(strategy === STRATEGIES.NO_PREFIX) &&
         // no prefix for different domains
         !i18n.differentDomains
-
-    let path = (isPrefixed ? `/${locale}${route.path}` : route.path)
-    path = path.replace(/\/+$/, '') + (trailingSlash ? '/' : '') || '/'
-    localizedRoute.path = path
+    const resolvedRoute = this.router.resolve(route.path).route
+    const resolvedRouteName = this.getRouteBaseName(resolvedRoute)
+    if (resolvedRouteName) {
+      localizedRoute = {
+        name: getLocaleRouteName(resolvedRouteName, locale),
+        params: resolvedRoute.params,
+        query: resolvedRoute.query,
+        hash: resolvedRoute.hash,
+        path: route.path
+      }
+    } else {
+      if (isPrefixed) {
+        localizedRoute.path = `/${locale}${route.path}`
+      }
+      localizedRoute.path = localizedRoute.path.replace(/\/+$/, '') + (trailingSlash ? '/' : '') || '/'
+    }
   } else {
     if (!route.name && !route.path) {
       localizedRoute.name = this.getRouteBaseName()

test/browser.test.js

@@ -637,6 +637,14 @@ describe(`${browserString} (SPA)`, () => {
     expect(await (await page.$('body'))?.textContent()).toContain('page could not be found')
     expect(await getRouteFullPath(page)).toBe(path)
   })
+
+  test('preserves the URL on 404 page with non-default locale', async () => {
+    const path = '/nopage?a#h'
+    page = await browser.newPage({ locale: 'fr' })
+    await page.goto(url(path))
+    expect(await (await page.$('body'))?.textContent()).toContain('page could not be found')
+    expect(await getRouteFullPath(page)).toBe(`/fr${path}`)
+  })
 })
 
 describe(`${browserString} (SPA with router in hash mode)`, () => {

test/module.test.js

@@ -1035,6 +1035,20 @@ describe('prefix_and_default strategy', () => {
     expect(window.$nuxt.localeRoute('/simple', 'fr')).toMatchObject({ name: 'simple___fr', fullPath: '/fr/simple' })
   })
 
+  test('localeRoute returns customized localized route (by route path)', async () => {
+    const window = await nuxt.renderAndGetWindow(url('/'))
+    // Prefer unprefixed path for default locale:
+    expect(window.$nuxt.localeRoute('/about-us', 'en')).toMatchObject({ name: 'about___en___default', fullPath: '/about-us' })
+    expect(window.$nuxt.localeRoute('/en/about-us', 'en')).toMatchObject({ name: 'about___en___default', fullPath: '/about-us' })
+    expect(window.$nuxt.localeRoute('/about-us', 'fr')).toMatchObject({ name: 'about___fr', fullPath: '/fr/a-propos' })
+    expect(window.$nuxt.localeRoute('/about-us?q=1#hash', 'en')).toMatchObject({
+      name: 'about___en___default',
+      fullPath: '/about-us?q=1#hash',
+      query: { q: '1' },
+      hash: '#hash'
+    })
+  })
+
   test('canonical SEO link is added to prefixed default locale', async () => {
     const html = await get('/en')
     const dom = getDom(html)