fix(timestamps): apply timestamps when creating new subdocs with $addToSet and with positional operator

Fix #10447

Author: vkarpov15

lib/helpers/update/applyTimestampsToChildren.js

@@ -19,34 +19,10 @@ function applyTimestampsToChildren(now, update, schema) {
 
   if (hasDollarKey) {
     if (update.$push) {
-      for (const key of Object.keys(update.$push)) {
-        const $path = schema.path(key);
-        if (update.$push[key] &&
-            $path &&
-            $path.$isMongooseDocumentArray &&
-            $path.schema.options.timestamps) {
-          const timestamps = $path.schema.options.timestamps;
-          const createdAt = handleTimestampOption(timestamps, 'createdAt');
-          const updatedAt = handleTimestampOption(timestamps, 'updatedAt');
-          if (update.$push[key].$each) {
-            update.$push[key].$each.forEach(function(subdoc) {
-              if (updatedAt != null) {
-                subdoc[updatedAt] = now;
-              }
-              if (createdAt != null) {
-                subdoc[createdAt] = now;
-              }
-            });
-          } else {
-            if (updatedAt != null) {
-              update.$push[key][updatedAt] = now;
-            }
-            if (createdAt != null) {
-              update.$push[key][createdAt] = now;
-            }
-          }
-        }
-      }
+      _applyTimestampToUpdateOperator(update.$push);
+    }
+    if (update.$addToSet) {
+      _applyTimestampToUpdateOperator(update.$addToSet);
     }
     if (update.$set != null) {
       const keys = Object.keys(update.$set);
@@ -60,6 +36,37 @@ function applyTimestampsToChildren(now, update, schema) {
   for (const key of updateKeys) {
     applyTimestampsToUpdateKey(schema, key, update, now);
   }
+
+  function _applyTimestampToUpdateOperator(op) {
+    for (const key of Object.keys(op)) {
+      const $path = schema.path(key.replace(/\.\$\./i, '.').replace(/.\$$/, ''));
+      if (op[key] &&
+          $path &&
+          $path.$isMongooseDocumentArray &&
+          $path.schema.options.timestamps) {
+        const timestamps = $path.schema.options.timestamps;
+        const createdAt = handleTimestampOption(timestamps, 'createdAt');
+        const updatedAt = handleTimestampOption(timestamps, 'updatedAt');
+        if (op[key].$each) {
+          op[key].$each.forEach(function(subdoc) {
+            if (updatedAt != null) {
+              subdoc[updatedAt] = now;
+            }
+            if (createdAt != null) {
+              subdoc[createdAt] = now;
+            }
+          });
+        } else {
+          if (updatedAt != null) {
+            op[key][updatedAt] = now;
+          }
+          if (createdAt != null) {
+            op[key][createdAt] = now;
+          }
+        }
+      }
+    }
+  }
 }
 
 function applyTimestampsToDocumentArray(arr, schematype, now) {