diff --git a/packages/common/src/client/AbstractPowerSyncDatabase.ts b/packages/common/src/client/AbstractPowerSyncDatabase.ts
index b8067fe7..cf512ae5 100644
--- a/packages/common/src/client/AbstractPowerSyncDatabase.ts
+++ b/packages/common/src/client/AbstractPowerSyncDatabase.ts
@@ -185,7 +185,7 @@ export abstract class AbstractPowerSyncDatabase extends BaseObserver<PowerSyncDB
 
     const { database, schema } = options;
 
-    if (false == schema instanceof Schema) {
+    if (typeof schema?.toJSON != 'function') {
       throw new Error('The `schema` option should be provided and should be an instance of `Schema`.');
     }