feat: add nuxt-i18n routes support with alternate links by hreflang

fix #91

README.md

@@ -15,6 +15,7 @@
 - Module based on the awesome **[sitemap.js](https://github.com/ekalinin/sitemap.js) package** ❤️
 - Create **sitemap** or **sitemap index**
 - Automatically add the static routes to each sitemap
+- Support **i18n** routes from **nuxt-i18n** (latest version)
 - Works with **all modes** (SSR, SPA, generate)
 - For **Nuxt 2.x** and higher
 
@@ -343,6 +344,50 @@ Add a trailing slash to each route URL (eg. `/page/1` => `/page/1/`)
 
 > **notice:** To avoid [duplicate content](https://support.google.com/webmasters/answer/66359) detection from crawlers, you have to configure an HTTP 301 redirect between the 2 URLs (see [redirect-module](https://github.com/nuxt-community/redirect-module) or [nuxt-trailingslash-module](https://github.com/WilliamDASILVA/nuxt-trailingslash-module)).
 
+### `i18n` (optional) - string | object
+
+- Default: `undefined`
+
+Configure the support of localized routes from **[nuxt-i18n](https://www.npmjs.com/package/nuxt-i18n)** module.
+
+If the `i18n` option is configured, the sitemap module will automatically add the default locale URL of each page in a `<loc>` element, with child `<xhtml:link>` entries listing every language/locale variant of the page including itself (see [Google sitemap guidelines](https://support.google.com/webmasters/answer/189077)).
+
+Examples:
+
+```js
+// nuxt.config.js
+
+{
+  modules: [
+    'nuxt-i18n',
+    '@nuxtjs/sitemap'
+  ],
+  i18n: {
+    locales: ['en', 'es', 'fr'],
+    defaultLocale: 'en'
+  },
+  sitemap: {
+    hostname: 'https://example.com',
+    // shortcut notation (basic)
+    i18n: 'en',
+    // nuxt-i18n notation (advanced)
+    i18n: {
+      defaultLocale: 'en',
+      routesNameSeparator: '___'
+    }
+  }
+}
+```
+
+```xml
+  <url>
+    <loc>https://example.com/</loc>
+    <xhtml:link rel="alternate" hreflang="en" href="https://example.com/"/>
+    <xhtml:link rel="alternate" hreflang="es" href="https://example.com/es/"/>
+    <xhtml:link rel="alternate" hreflang="fr" href="https://example.com/fr/"/>
+  </url>
+```
+
 ### `defaults` (optional) - object
 
 - Default: `{}`

lib/builder.js

@@ -44,7 +44,53 @@ function createSitemap(options, routes, base = null, req = null) {
     })
   }
 
-  // Enable filter function for each declared route
+  // Group each route with its alternative languages
+  if (options.i18n) {
+    const { defaultLocale, routesNameSeparator } = options.i18n
+
+    // Set alternate routes for each page
+    const i18nRoutes = routes.reduce((i18nRoutes, route, index) => {
+      if (!route.name) {
+        // Route without alternate link
+        i18nRoutes[`#${index}`] = route
+        return i18nRoutes
+      }
+
+      let [page, lang, isDefault] = route.name.split(routesNameSeparator) // eslint-disable-line prefer-const
+
+      // Get i18n route, or init it
+      const i18nRoute = i18nRoutes[page] || { ...route }
+
+      if (lang) {
+        // Set main link
+        if (isDefault) {
+          lang = 'x-default'
+        }
+        if (lang === defaultLocale) {
+          i18nRoute.url = route.url
+        }
+
+        // Set alternate links
+        if (!i18nRoute.links) {
+          i18nRoute.links = []
+        }
+        i18nRoute.links.push({
+          lang,
+          url: route.url,
+        })
+      } else {
+        // No alternate link found
+        i18nRoute.url = route.url
+      }
+
+      i18nRoutes[page] = i18nRoute
+      return i18nRoutes
+    }, {})
+
+    routes = Object.values(i18nRoutes)
+  }
+
+  // Enable the custom filter function for each declared route
   if (typeof options.filter === 'function') {
     routes = options.filter({
       options: { ...sitemapConfig },

lib/options.js

@@ -1,3 +1,5 @@
+const MODULE_NAME = require('../package.json').name
+
 const logger = require('./logger')
 
 const DEFAULT_NUXT_PUBLIC_PATH = '/_nuxt/'
@@ -27,6 +29,7 @@ function setDefaultSitemapOptions(options, nuxtInstance, isLinkedToSitemapIndex
     xslUrl: undefined,
     trailingSlash: false,
     lastmod: undefined,
+    i18n: undefined,
     defaults: {},
   }
 
@@ -35,6 +38,31 @@ function setDefaultSitemapOptions(options, nuxtInstance, isLinkedToSitemapIndex
     ...options,
   }
 
+  if (sitemapOptions.i18n) {
+    // Check modules config
+    const modules = Object.keys(nuxtInstance.requiredModules)
+    /* istanbul ignore if */
+    if (modules.indexOf('nuxt-i18n') > modules.indexOf(MODULE_NAME)) {
+      logger.warn(
+        `To enable the "i18n" option, the "${MODULE_NAME}" must be declared after the "nuxt-i18n" module in your config`
+      )
+    }
+
+    // Shortcut notation
+    if (typeof sitemapOptions.i18n === 'string') {
+      sitemapOptions.i18n = {
+        defaultLocale: sitemapOptions.i18n,
+      }
+    }
+
+    // Set default i18n options
+    sitemapOptions.i18n = {
+      defaultLocale: '',
+      routesNameSeparator: '___',
+      ...sitemapOptions.i18n,
+    }
+  }
+
   /* istanbul ignore if */
   if (sitemapOptions.generate) {
     logger.warn("The `generate` option isn't needed anymore in your config. Please remove it!")

package.json

@@ -72,6 +72,7 @@
     "jest": "latest",
     "lint-staged": "latest",
     "nuxt": "latest",
+    "nuxt-i18n": "latest",
     "prettier": "latest",
     "request-promise-native": "latest",
     "standard-version": "latest"

test/module.test.js

@@ -7,6 +7,7 @@ const request = require('request-promise-native')
 
 const config = require('./fixture/nuxt.config')
 config.dev = false
+config.modules = [require('..')]
 config.sitemap = {}
 
 const url = (path) => `http://localhost:3000${path}`
@@ -329,8 +330,6 @@ describe('sitemap - advanced configuration', () => {
       })
 
       const xml = await get('/sitemap.xml')
-
-      // trailing slash
       expect(xml).not.toContain('<loc>https://example.com/sub</loc>')
       expect(xml).not.toContain('<loc>https://example.com/sub/sub</loc>')
       expect(xml).not.toContain('<loc>https://example.com/test</loc>')
@@ -340,6 +339,111 @@ describe('sitemap - advanced configuration', () => {
     })
   })
 
+  describe('i18n options', () => {
+    const modules = [require('nuxt-i18n'), require('..')]
+
+    const nuxtI18nConfig = {
+      locales: ['en', 'fr'],
+      defaultLocale: 'en',
+    }
+
+    const sitemapConfig = {
+      hostname: 'https://example.com',
+      trailingSlash: true,
+      i18n: 'en',
+      routes: ['foo', { url: 'bar' }],
+    }
+
+    test('strategy "no_prefix"', async () => {
+      nuxt = await startServer({
+        ...config,
+        modules,
+        i18n: {
+          ...nuxtI18nConfig,
+          strategy: 'no_prefix',
+        },
+        sitemap: sitemapConfig,
+      })
+
+      const xml = await get('/sitemap.xml')
+      expect(xml).toContain('<loc>https://example.com/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/en/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/fr/</loc>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/"/>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/"/>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="fr" href="https://example.com/fr/"/>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/"/>')
+    })
+
+    test('strategy "prefix"', async () => {
+      nuxt = await startServer({
+        ...config,
+        modules,
+        i18n: {
+          ...nuxtI18nConfig,
+          strategy: 'prefix',
+        },
+        sitemap: sitemapConfig,
+      })
+
+      const xml = await get('/sitemap.xml')
+      expect(xml).not.toContain('<loc>https://example.com/</loc>')
+      expect(xml).toContain('<loc>https://example.com/en/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/fr/</loc>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/"/>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/"/>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="fr" href="https://example.com/fr/"/>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/"/>')
+    })
+
+    test('strategy "prefix_except_default"', async () => {
+      nuxt = await startServer({
+        ...config,
+        modules,
+        i18n: {
+          ...nuxtI18nConfig,
+          strategy: 'prefix_except_default',
+        },
+        sitemap: sitemapConfig,
+      })
+
+      const xml = await get('/sitemap.xml')
+      expect(xml).toContain('<loc>https://example.com/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/en/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/fr/</loc>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/"/>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/"/>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="fr" href="https://example.com/fr/"/>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/"/>')
+    })
+
+    test('strategy "prefix_and_default"', async () => {
+      nuxt = await startServer({
+        ...config,
+        modules,
+        i18n: {
+          ...nuxtI18nConfig,
+          strategy: 'prefix_and_default',
+        },
+        sitemap: {
+          ...sitemapConfig,
+          i18n: {
+            defaultLocale: 'x-default',
+          },
+        },
+      })
+
+      const xml = await get('/sitemap.xml')
+      expect(xml).toContain('<loc>https://example.com/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/en/</loc>')
+      expect(xml).not.toContain('<loc>https://example.com/fr/</loc>')
+      expect(xml).not.toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/"/>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/"/>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="fr" href="https://example.com/fr/"/>')
+      expect(xml).toContain('<xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/"/>')
+    })
+  })
+
   describe('external options', () => {
     test('default hostname from build.publicPath', async () => {
       nuxt = await startServer({