Merge pull request #668 from streamich/fix-nested-transactions

Allow nested transactions

Author: streamich

src/json-crdt/json-patch/__tests__/JsonPatchStore.spec.ts

@@ -103,3 +103,30 @@ test('can bind store to a "str" node', async () => {
   store2.update({op: 'str_ins', path: '', pos: 3, str: 'x'});
   expect(store2.getSnapshot()).toEqual('abcx');
 });
+
+test('can execute mutations inside a transaction', async () => {
+  const model = Model.create(
+    s.obj({
+      ui: s.obj({
+        state: s.obj({
+          text: s.str('abc'),
+          counter: s.con(123),
+        }),
+      }),
+    }),
+  );
+  const store = new JsonPatchStore(model, ['ui']);
+  const store2 = store.bind('/state/text');
+  expect(store2.getSnapshot()).toEqual('abc');
+  let cnt = 0;
+  model.api.onTransaction.listen(() => {
+    cnt++;
+  });
+  model.api.transaction(() => {
+    store2.update({op: 'str_ins', path: '', pos: 3, str: 'x'});
+  });
+  expect(cnt).toBe(1);
+  await tick(1);
+  expect(cnt).toBe(1);
+  expect(store2.getSnapshot()).toEqual('abcx');
+});

src/json-crdt/model/api/ModelApi.ts

@@ -262,10 +262,19 @@ export class ModelApi<N extends JsonNode = JsonNode> implements SyncStore<JsonNo
     return this.model.view();
   }
 
+  private inTx = false;
   public transaction(callback: () => void) {
-    this.onBeforeTransaction.emit();
-    callback();
-    this.onTransaction.emit();
+    if (this.inTx) callback();
+    else {
+      this.inTx = true;
+      try {
+        this.onBeforeTransaction.emit();
+        callback();
+        this.onTransaction.emit();
+      } finally {
+        this.inTx = false;
+      }
+    }
   }
 
   /**