1 files changed, 7 insertions, 4 deletions
diff --git a/src/client/DocServer.ts b/src/client/DocServer.ts
index 5af89cf49..977eb7772 100644
--- a/src/client/DocServer.ts
+++ b/src/client/DocServer.ts
@@ -33,7 +33,7 @@ export namespace DocServer {
     }
 
     const fieldWriteModes: { [field: string]: WriteMode } = {};
-    const docsWithUpdates: { [field: string]: Doc[] } = {};
+    const docsWithUpdates: { [field: string]: Set<Doc> } = {};
 
     export function setFieldWriteMode(field: string, writeMode: WriteMode) {
         fieldWriteModes[field] = writeMode;
@@ -50,12 +50,15 @@ export namespace DocServer {
         return fieldWriteModes[field];
     }
 
-    export function registerDocWithCachedUpdate(doc: Doc, field: string) {
+    export function registerDocWithCachedUpdate(doc: Doc, field: string, oldValue: any) {
         let list = docsWithUpdates[field];
         if (!list) {
-            list = docsWithUpdates[field] = [];
+            list = docsWithUpdates[field] = new Set;
+        }
+        if (!list.has(doc)) {
+            Doc.AddCachedUpdate(doc, field, oldValue);
+            list.add(doc);
         }
-        list.push(doc);
     }
 
     export function init(protocol: string, hostname: string, port: number, identifier: string) {