Reading the right data payload from TTN in Node-red

Hi All,

I’ve successfully connected my Lora WiFi V3 mode to the HT-M01S and now I can receive the node data in node-red. In my arduino code (shared folder), I just send text “{hello}” and try to decode in node-red at the debug node. Attached please find my flow in node-red in my shared folder.
I have also configure the data formatter in TTN such that data bytes can be seem in node-red.

I can see the data bytes received from my MQTT nodes. However, I cannot get the data out of the packet using Javascript function. I always receive the error “SyntaxError: Unexpected token o in JSON at position 1”.
Could anyone can help me to resolve this? Thanks!!
Here is the link of my shared files: