Support a new language query param

middleware/context-builder.js

@@ -8,13 +8,20 @@ module.exports = function contextBuilder (req, res, next) {
   // Attach i18n object to request so any route handler can use it if needed
   req.i18n = i18n
 
-  const localized = i18n.website[req.language]
+  // This allows the language to be set per-request using a query param, so
+  // folks can share a link like /docs/api/app?language=fr-FR and know that
+  // the recipient will see the doc in that language, regardless of their
+  // language settings. If no query param is set, fall back to the default
+  // language (or the one set in the cookie)
+  const targetLanguage = req.query.language || req.language
+
+  const localized = i18n.website[targetLanguage]
 
   // Page titles, descriptions, etc
   let page = Object.assign({
     title: 'Electron',
     path: req.path
-  }, i18n.website[req.language].pages[req.path])
+  }, i18n.website[targetLanguage].pages[req.path])
 
   if (req.path !== '/') {
     page.title = `${page.title} | Electron`
@@ -34,7 +41,7 @@ module.exports = function contextBuilder (req, res, next) {
   }
 
   if (req.path.startsWith('/docs')) {
-    req.context.docs = i18n.docs[req.language]
+    req.context.docs = i18n.docs[targetLanguage]
   }
 
   return next()

test/index.js

@@ -267,10 +267,20 @@ describe('electronjs.org', () => {
     })
   })
 
-  test('/languages', async () => {
-    const $ = await get('/languages')
-    $('h1').text().should.eq('Languages')
-    $('body').text().should.include('global developer community')
+  describe('languages', () => {
+    test('/languages', async () => {
+      const $ = await get('/languages')
+      $('h1').text().should.eq('Languages')
+      $('body').text().should.include('global developer community')
+    })
+
+    test('language query param for one-off viewing in other languages', async () => {
+      let $ = await get('/docs/api/browser-window?language=fr-FR')
+      $('body').text().should.include('fenêtres')
+
+      $ = await get('/docs/api/browser-window')
+      $('body').text().should.not.include('fenêtres')
+    })
   })
 
   test('redirects for date-style blog URLs', async () => {