Adds `page.lang` when using i18n plugin! Fixes #2501 prerequisite of #243 eleventy-base-blog

src/Plugins/I18nPlugin.js

@@ -11,6 +11,11 @@ const bcp47Normalize = require("bcp-47-normalize");
 const iso639 = require("iso-639-1");
 
 class LangUtils {
+  static getLanguageCodeFromUrl(url) {
+    let s = (url || "").split("/");
+    return s.length > 0 && Comparator.isLangCode(s[1]) ? s[1] : "";
+  }
+
   static swapLanguageCode(str, langCode) {
     if (!Comparator.isLangCode(langCode)) {
       return str;
@@ -197,20 +202,27 @@ function EleventyPlugin(eleventyConfig, opts = {}) {
     }
   );
 
+  eleventyConfig.addGlobalData("eleventyComputed.page.lang", () => {
+    // if addGlobalData receives a function it will execute it immediately,
+    // so we return a nested function for computed data
+    return (data) => {
+      return (
+        LangUtils.getLanguageCodeFromUrl(data.page.url) ||
+        options.defaultLanguage
+      );
+    };
+  });
+
   // Normalize a theoretical URL based on the current page’s language
   // If a non-localized file exists, returns the URL without a language assigned
   // Fails if no file exists (localized and not localized)
   eleventyConfig.addFilter(
     options.filters.url,
     function (url, langCodeOverride) {
-      let langCode = langCodeOverride;
-      if (!langCode) {
-        let pageUrl = getPageInFilter(this)?.url;
-        let s = pageUrl.split("/");
-        langCode =
-          (s.length > 0 && Comparator.isLangCode(s[1]) ? s[1] : "") ||
-          options.defaultLanguage;
-      }
+      let langCode =
+        langCodeOverride ||
+        LangUtils.getLanguageCodeFromUrl(getPageInFilter(this)?.url) ||
+        options.defaultLanguage;
 
       // Already has a language code on it and has a relevant url with the target language code
       if (

test/I18nPluginTest.js

@@ -148,7 +148,8 @@ test("locale_url and locale_links Filters", async (t) => {
 /en-us/
 /non-lang-file/
 []
-[]`
+[]
+en`
   );
 
   t.is(
@@ -159,7 +160,8 @@ test("locale_url and locale_links Filters", async (t) => {
 /en-us/
 /non-lang-file/
 [{"url":"/en/","lang":"en","label":"English"},{"url":"/en-us/","lang":"en-us","label":"English"}]
-[{"url":"/en/","lang":"en","label":"English"},{"url":"/en-us/","lang":"en-us","label":"English"}]`
+[{"url":"/en/","lang":"en","label":"English"},{"url":"/en-us/","lang":"en-us","label":"English"}]
+es`
   );
 
   t.is(
@@ -170,7 +172,8 @@ test("locale_url and locale_links Filters", async (t) => {
 /en-us/
 /non-lang-file/
 [{"url":"/en-us/","lang":"en-us","label":"English"},{"url":"/es/","lang":"es","label":"Español"}]
-[{"url":"/en-us/","lang":"en-us","label":"English"},{"url":"/es/","lang":"es","label":"Español"}]`
+[{"url":"/en-us/","lang":"en-us","label":"English"},{"url":"/es/","lang":"es","label":"Español"}]
+en`
   );
 
   t.is(
@@ -181,6 +184,7 @@ test("locale_url and locale_links Filters", async (t) => {
 /es/
 /non-lang-file/
 [{"url":"/en/","lang":"en","label":"English"},{"url":"/es/","lang":"es","label":"Español"}]
-[{"url":"/en/","lang":"en","label":"English"},{"url":"/es/","lang":"es","label":"Español"}]`
+[{"url":"/en/","lang":"en","label":"English"},{"url":"/es/","lang":"es","label":"Español"}]
+en-us`
   );
 });

test/stubs-i18n/en-us/index.11ty.js

@@ -5,5 +5,6 @@ ${this.locale_url("/es/")}
 ${this.locale_url("/", "es")}
 ${this.locale_url("/non-lang-file/")}
 ${JSON.stringify(this.locale_links(data.page.url).sort())}
-${JSON.stringify(this.locale_links().sort())}`;
+${JSON.stringify(this.locale_links().sort())}
+${data.page.lang}`;
 };

test/stubs-i18n/en/index.liquid

@@ -4,4 +4,5 @@
 {{ "/" | locale_url: "en-us" }}
 {{ "/non-lang-file/" | locale_url }}
 {{ page.url | locale_links | json }}
-{{ "" | locale_links | json }}
\ No newline at end of file
+{{ "" | locale_links | json }}
+{{ page.lang }}
\ No newline at end of file

test/stubs-i18n/es/index.njk

@@ -4,4 +4,5 @@
 {{ "/" | locale_url("en-us") }}
 {{ "/non-lang-file/" | locale_url }}
 {{ page.url | locale_links | dump | safe }}
-{{ "" | locale_links | dump | safe }}
\ No newline at end of file
+{{ "" | locale_links | dump | safe }}
+{{ page.lang }}
\ No newline at end of file

test/stubs-i18n/non-lang-file.njk

@@ -2,4 +2,5 @@
 {{ "/" | locale_url("en-us") }}
 {{ "/non-lang-file/" | locale_url }}
 {{ page.url | locale_links | dump | safe }}
-{{ "" | locale_links | dump | safe }}
\ No newline at end of file
+{{ "" | locale_links | dump | safe }}
+{{ page.lang }}
\ No newline at end of file