feat: Add canonical link to PREFIX_AND_DEFAULT duplicated pages (#194)

Nabellaleen · paulgv · commit dcd1f7957039 · 2019-01-20T10:43:18.000-05:00
diff --git a/docs/seo.md b/docs/seo.md
@@ -5,6 +5,8 @@ By default, **nuxt-i18n** attempts to add some metadata to improve your pages SE
 * Add a _lang_ attribute containing current locale's ISO code to the `<html>` tag.
 * Generate `<link rel="alternate" hreflang="x">` tags for every language configured in `nuxt.config.js`. For each language, the ISO code is used as `hreflang` attribute's value. [More on hreflang](https://support.google.com/webmasters/answer/189077)
 * Generate `og:locale` and `og:locale:alternate` meta tags as defined in the [Open Graph protocol](http://ogp.me/#optional)
+* When using `prefix_and_default` strategy, generate `rel="canonical"` link on the default language routes containing the 
+prefix to avoid duplicate indexation. [More on canonical](https://support.google.com/webmasters/answer/182192#dup-content)
 
 
 For this feature to work, you must configure `locales` option as an array of objects, where each object has an `iso` option set to the language ISO code:
diff --git a/src/index.js b/src/index.js
@@ -13,6 +13,7 @@ const {
   LOCALE_ISO_KEY,
   LOCALE_DOMAIN_KEY,
   LOCALE_FILE_KEY,
+  STRATEGIES,
   COMPONENT_OPTIONS_KEY
 } = require('./helpers/constants')
 
@@ -46,6 +47,7 @@ module.exports = function (userOptions) {
     LOCALE_ISO_KEY,
     LOCALE_DOMAIN_KEY,
     LOCALE_FILE_KEY,
+    STRATEGIES,
     COMPONENT_OPTIONS_KEY,
     getLocaleCodes,
     getLocaleFromRoute,
diff --git a/src/templates/seo-head.js b/src/templates/seo-head.js
@@ -12,6 +12,7 @@ export const nuxtI18nSeo = function () {
   const LOCALE_CODE_KEY = '<%= options.LOCALE_CODE_KEY %>'
   const LOCALE_ISO_KEY = '<%= options.LOCALE_ISO_KEY %>'
   const BASE_URL = '<%= options.baseUrl %>'
+  const STRATEGY = '<%= options.strategy %>'
 
   // Prepare html lang attribute
   const currentLocaleData = this.$i18n.locales.find(l => l[LOCALE_CODE_KEY] === this.$i18n.locale)
@@ -37,6 +38,19 @@ export const nuxtI18nSeo = function () {
     })
     .filter(item => !!item)
 
+  // canonical links
+  if (STRATEGY === '<%= options.STRATEGIES.PREFIX_AND_DEFAULT %>') {
+    const canonicalPath = this.switchLocalePath(currentLocaleData[LOCALE_CODE_KEY])
+    if (canonicalPath && canonicalPath !== this.$route.path) {
+      // Current page is not the canonical one -- add a canonical link
+      link.push({
+        hid: 'canonical-lang-' + currentLocaleData[LOCALE_CODE_KEY],
+        rel: "canonical",
+        href: BASE_URL + canonicalPath
+      })
+    }
+  }
+
   // og:locale meta
   const meta = []
   // og:locale - current
