lib/explore.mjs

@@ -10,10 +10,9 @@ const GRAPH_LINK = '    "%s" -> "%s"';
  *
  * @async
  * @param string videoId Source video identifier.
- * @param function onUpdate Callback run every time a new video is explored.
  * @return Array.<Object, Object> Nodes and set of neighbors of each node.
  */
-export const exploreVideos = async (videoId, onUpdate) =>
+export const exploreVideos = async videoId =>
 {
     // Store metadata about each visited video
     const videosNodes = Object.create(null);
@@ -28,28 +27,25 @@ export const exploreVideos = async (videoId, onUpdate) =>
     while (queue.length > 0)
     {
         const currentId = queue.shift();
+        const config = await api.getPlayerConfig(currentId);
+        const meta = api.getVideoMeta(config);
 
-        if (!(currentId in videosNodes))
+        videosNodes[currentId] = meta;
+        nextVideos[currentId] = new Set();
+
+        // Add links between this video and the linked ones
+        api.getEndScreenVideos(config)
+            .forEach(nextId => nextVideos[meta.videoId].add(nextId));
+        api.getCardVideos(config)
+            .forEach(nextId => nextVideos[meta.videoId].add(nextId));
+
+        for (let nextId of nextVideos[meta.videoId])
         {
-            const config = await api.getPlayerConfig(currentId);
-            const meta = api.getVideoMeta(config);
-
-            videosNodes[currentId] = meta;
-            nextVideos[currentId] = new Set();
-
-            // Add links between this video and the linked ones
-            api.getEndScreenVideos(config)
-                .forEach(nextId => nextVideos[meta.videoId].add(nextId));
-            api.getCardVideos(config)
-                .forEach(nextId => nextVideos[meta.videoId].add(nextId));
-
-            for (let nextId of nextVideos[meta.videoId])
+            if (!(nextId in videosNodes))
             {
                 queue.push(nextId);
             }
         }
-
-        onUpdate(Object.keys(videosNodes).length, queue.length);
     }
 
     return [videosNodes, nextVideos];

routes/mazes.mjs

@@ -5,7 +5,6 @@ import { toSVG } from '../lib/graphviz.mjs';
 const router = express.Router();
 export default router;
 
-const statusDone = Symbol('DONE');
 const statusPending = Symbol('PENDING');
 const statusError = Symbol('ERROR');
 const cache = Object.create(null);
@@ -46,47 +45,37 @@ router.get('/:videoId', async (req, res) => {
 
     if (videoId in cache)
     {
-        if (cache[videoId][0] === statusPending)
+        if (cache[videoId] === statusPending)
         {
             res.header('Refresh', '5');
-            res.send(`Exploration in progress, please wait.<br>
-${cache[videoId][1]}…`);
+            res.send('Exploration in progress… Please wait.');
         }
-        else if (cache[videoId][0] === statusError)
+        else if (cache[videoId] === statusError)
         {
             res.status(500).send('Error');
         }
         else
         {
-            res.send(cache[videoId][1]);
+            res.send(cache[videoId]);
         }
     }
     else
     {
-        cache[videoId] = [statusPending, 'Starting exploration'];
+        cache[videoId] = statusPending;
         res.header('Refresh', '1');
-        res.send('Exploration in progress, please wait.');
+        res.send('Exploration in progress… Please wait.');
 
         try
         {
-            const graph = await exploreVideos(req.params.videoId, (done, rem) =>
-            {
-                cache[videoId] = [
-                    statusPending,
-                    `${done} videos explored, ${rem} pending`
-                ];
-            });
-
-            cache[videoId] = [statusPending, 'Converting graph to SVG'];
+            const graph = await exploreVideos(req.params.videoId);
             const graphviz = toGraphviz(...graph);
             const svg = await toSVG(graphviz);
-
-            cache[videoId] = [statusDone, svg];
+            cache[videoId] = svg;
         }
         catch (err)
         {
             console.error(err);
-            cache[videoId] = [statusError];
+            cache[videoId] = statusError;
         }
     }
 });