For further reference, here is the results of the equivalent code under Chrome's Web Bluetooth.
2 characteristics [READ, NOTIFY] 803c3b1f-d300-1120-0530-33a62b7838c9 Found cmd_rx characteristic Notifications started. [WRITEWITHOUTRESPONSE] 803c3b1f-d300-1120-0530-33a62b7838c9 Found cmd_tx characteristic
@user125533 started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
For further reference, here is the results of the equivalent code under Chrome's Web Bluetooth.