toDelta doesnt create transaction - fixes #506

src/types/YText.js

@@ -1018,15 +1018,7 @@ export class YText extends AbstractType {
         str = ''
       }
     }
-    // snapshots are merged again after the transaction, so we need to keep the
-    // transalive until we are done
-    transact(doc, transaction => {
-      if (snapshot) {
-        splitSnapshotAffectedStructs(transaction, snapshot)
-      }
-      if (prevSnapshot) {
-        splitSnapshotAffectedStructs(transaction, prevSnapshot)
-      }
+    const computeDelta = () => {
       while (n !== null) {
         if (isVisible(n, snapshot) || (prevSnapshot !== undefined && isVisible(n, prevSnapshot))) {
           switch (n.content.constructor) {
@@ -1079,7 +1071,22 @@ export class YText extends AbstractType {
         n = n.right
       }
       packStr()
-    }, 'cleanup')
+    }
+    if (snapshot || prevSnapshot) {
+      // snapshots are merged again after the transaction, so we need to keep the
+      // transaction alive until we are done
+      transact(doc, transaction => {
+        if (snapshot) {
+          splitSnapshotAffectedStructs(transaction, snapshot)
+        }
+        if (prevSnapshot) {
+          splitSnapshotAffectedStructs(transaction, prevSnapshot)
+        }
+        computeDelta()
+      }, 'cleanup')
+    } else {
+      computeDelta()
+    }
     return ops
   }
 

src/types/YXmlFragment.js

@@ -257,8 +257,7 @@ export class YXmlFragment extends AbstractType {
    * @return {string} The string representation of all children.
    */
   toString () {
-    // toString can result in many cleanup transactions. We wrap all cleanup transactions here to reduce the work
-    return transact(/** @type {Doc} */ (this.doc), () => typeListMap(this, xml => xml.toString()).join(''))
+    return typeListMap(this, xml => xml.toString()).join('')
   }
 
   /**

src/utils/Doc.js

@@ -156,13 +156,15 @@ export class Doc extends Observable {
    * that happened inside of the transaction are sent as one message to the
    * other peers.
    *
-   * @param {function(Transaction):void} f The function that should be executed as a transaction
+   * @template T
+   * @param {function(Transaction):T} f The function that should be executed as a transaction
    * @param {any} [origin] Origin of who started the transaction. Will be stored on transaction.origin
+   * @return T
    *
    * @public
    */
   transact (f, origin = null) {
-    transact(this, f, origin)
+    return transact(this, f, origin)
   }
 
   /**

tests/doc.tests.js

@@ -33,7 +33,7 @@ export const testOriginInTransaction = _tc => {
   doc.on('afterTransaction', (tr) => {
     origins.push(tr.origin)
     if (origins.length <= 1) {
-      ytext.toDelta()
+      ytext.toDelta(Y.snapshot(doc)) // adding a snapshot forces toDelta to create a cleanup transaction
       doc.transact(() => {
         ytext.insert(0, 'a')
       }, 'nested')