From eb4dfbad9268b25f7e1a289d8d91bfe9f7557716 Mon Sep 17 00:00:00 2001
From: zadam <zadam.apps@gmail.com>
Date: Mon, 16 Dec 2019 22:47:07 +0100
Subject: [PATCH] sync fixes

---
 .../javascripts/services/tree_builder.js      |  2 +-
 src/public/javascripts/services/ws.js         | 24 ++++++++++++-------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/public/javascripts/services/tree_builder.js b/src/public/javascripts/services/tree_builder.js
index 70522af7c..eda30b55a 100644
--- a/src/public/javascripts/services/tree_builder.js
+++ b/src/public/javascripts/services/tree_builder.js
@@ -67,7 +67,7 @@ async function prepareNode(branch) {
     const note = await branch.getNote();
 
     if (!note) {
-        console.log(`Branch has no note: ${branch}`);
+        throw new Error(`Branch has no note ` + branch.noteId);
     }
 
     const title = (branch.prefix ? (branch.prefix + " - ") : "") + note.title;
diff --git a/src/public/javascripts/services/ws.js b/src/public/javascripts/services/ws.js
index b6bb40882..918ab8aee 100644
--- a/src/public/javascripts/services/ws.js
+++ b/src/public/javascripts/services/ws.js
@@ -59,6 +59,10 @@ async function handleMessage(event) {
 
             syncDataQueue.push(...syncRows);
 
+            // we set lastAcceptedSyncId even before sync processing and send ping so that backend can start sending more updates
+            lastAcceptedSyncId = Math.max(lastAcceptedSyncId, syncRows[syncRows.length - 1].id);
+            sendPing();
+
             // first wait for all the preceding consumers to finish
             while (consumeQueuePromise) {
                 await consumeQueuePromise;
@@ -132,15 +136,19 @@ async function consumeSyncData() {
 
         const outsideSyncData = allSyncData.filter(sync => sync.sourceId !== glob.sourceId);
 
-        // we set lastAcceptedSyncId even before sync processing and send ping so that backend can start sending more updates
-        lastAcceptedSyncId = Math.max(lastAcceptedSyncId, allSyncData[allSyncData.length - 1].id);
-        sendPing();
+        try {
+            // the update process should be synchronous as a whole but individual handlers can run in parallel
+            await Promise.all([
+                ...allSyncMessageHandlers.map(syncHandler => runSafely(syncHandler, allSyncData)),
+                ...outsideSyncMessageHandlers.map(syncHandler => runSafely(syncHandler, outsideSyncData))
+            ]);
+        }
+        catch (e) {
+            logError(`Encountered error ${e.message}, reloading frontend.`);
 
-        // the update process should be synchronous as a whole but individual handlers can run in parallel
-        await Promise.all([
-            ...allSyncMessageHandlers.map(syncHandler => runSafely(syncHandler, allSyncData)),
-            ...outsideSyncMessageHandlers.map(syncHandler => runSafely(syncHandler, outsideSyncData))
-        ]);
+            // if there's an error in updating the frontend then the easy option to recover is to reload the frontend completely
+            utils.reloadApp();
+        }
 
         lastProcessedSyncId = Math.max(lastProcessedSyncId, allSyncData[allSyncData.length - 1].id);
     }