feat: $lang and $localePath globals (#166) (#167)

close #166 

Co-authored-by: Kia King Ishii <kia.king.08@gmail.com>

docs/guide/global-computed.md

@@ -64,6 +64,14 @@ Reference of `$page.frontmatter`.
 }
 ```
 
+## $lang
+
+The language of the current page. Default: `en-US`.
+
+## $localePath
+
+The locale path prefix for the current page. Default: `/`.
+
 ## $title
 
 Value of the `<title>` label used for the current page.

src/client/app/mixin.ts

@@ -42,6 +42,25 @@ export function mixinGlobalComputed(
       }
     },
 
+    $lang: {
+      get() {
+        return siteByRoute.value.lang
+      }
+    },
+
+    $localePath: {
+      get() {
+        const { locales } = site.value
+        const { lang } = siteByRoute.value
+
+        const path = Object.keys(locales).find(
+          (lp) => locales[lp].lang === lang
+        )
+
+        return (locales && path) || '/'
+      }
+    },
+
     $title: {
       get() {
         return page.value.title