add runtime validation of appMetadata

Author: stevensJourney

demos/example-node/src/main.ts

@@ -58,12 +58,11 @@ const main = async () => {
     logger
   });
   console.log(await db.get('SELECT powersync_rs_version();'));
-
   await db.connect(new DemoConnector(), {
     connectionMethod: SyncStreamConnectionMethod.WEB_SOCKET,
     clientImplementation: SyncClientImplementation.RUST,
     appMetadata: {
-      package_version: process.env.npm_package_version || 'unknown'
+      app_version: process.env.npm_package_version || 'unknown'
     }
   });
   // Example using a proxy agent for more control over the connection:

packages/common/src/client/sync/stream/AbstractStreamingSyncImplementation.ts

@@ -664,6 +664,16 @@ The next upload iteration will be delayed.`);
           ...DEFAULT_STREAM_CONNECTION_OPTIONS,
           ...(options ?? {})
         };
+
+        // Validate app metadata
+        const invalidMetadata = Object.entries(resolvedOptions.appMetadata).filter(
+          ([_, value]) => typeof value != 'string'
+        );
+        if (invalidMetadata.length > 0) {
+          throw new Error(
+            `Invalid appMetadata provided. Only string values are allowed. Invalid values: ${invalidMetadata.map(([key, value]) => `${key}: ${value}`).join(', ')}`
+          );
+        }
         const clientImplementation = resolvedOptions.clientImplementation;
         this.updateSyncStatus({ clientImplementation });