move the learning tracks processing into a separate module and return featured link in addition to learning tracks

Author: sarahs

lib/page.js

@@ -11,6 +11,7 @@ const pathUtils = require('./path-utils')
 const Permalink = require('./permalink')
 const languages = require('./languages')
 const renderContent = require('./render-content')
+const processLearningTracks = require('./process-learning-tracks')
 const { renderReact } = require('./react/engine')
 const { productMap } = require('./all-products')
 const slash = require('slash')
@@ -207,23 +208,10 @@ class Page {
       this.permissions = await renderContent(this.rawPermissions, context)
     }
 
+    // Learning tracks may contain Liquid and need to have versioning processed.
     if (this.learningTracks) {
-      const learningTracks = []
-      for await (const rawTrackName of this.rawLearningTracks) {
-        // Track names in frontmatter may include Liquid conditionals
-        const renderedTrackName = await renderContent(rawTrackName, context, { textOnly: true, encodeEntities: true })
-        if (!renderedTrackName) continue
-
-        const track = context.site.data['learning-tracks'][context.currentProduct][renderedTrackName]
-        if (!track) continue
-        learningTracks.push({
-          trackName: renderedTrackName,
-          title: await renderContent(track.title, context, { textOnly: true, encodeEntities: true }),
-          description: await renderContent(track.description, context, { textOnly: true, encodeEntities: true }),
-          guides: await getLinkData(track.guides, context)
-        })
-      }
-
+      const { featuredTrack, learningTracks } = await processLearningTracks(this.rawLearningTracks, context)
+      this.featuredTrack = featuredTrack
       this.learningTracks = learningTracks
     }
 

lib/process-learning-tracks.js

@@ -0,0 +1,40 @@
+const renderContent = require('./render-content')
+const getLinkData = require('./get-link-data')
+
+const renderOpts = { textOnly: true, encodeEntities: true }
+
+module.exports = async function processLearningTracks (rawLearningTracks, context) {
+  const learningTracks = []
+
+  let featuredTrack
+
+  for await (const rawTrackName of rawLearningTracks) {
+    // Track names in frontmatter may include Liquid conditionals
+    const renderedTrackName = await renderContent(rawTrackName, context, renderOpts)
+    if (!renderedTrackName) continue
+
+    const track = context.site.data['learning-tracks'][context.currentProduct][renderedTrackName]
+    if (!track) continue
+
+    const learningTrack = {
+      trackName: renderedTrackName,
+      title: await renderContent(track.title, context, renderOpts),
+      description: await renderContent(track.description, context, renderOpts),
+      // getLinkData respects versioning and only returns guides available in the current version;
+      // if no guides are available, the learningTrack.guides property will be an empty array.
+      guides: await getLinkData(track.guides, context)
+    }
+
+    if (track.featured_track) {
+      // Set the featured track, which is not included in the array of other learning tracks.
+      featuredTrack = learningTrack
+    } else {
+      // Only add the track to the array of tracks if there are guides in this version.
+      if (learningTrack.guides.length) {
+        learningTracks.push(learningTrack)
+      }
+    }
+  }
+
+  return { featuredTrack, learningTracks }
+}