BluetoothRemoteGATTService: isPrimary property
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
  The BluetoothGATTService.isPrimary read-only property
  returns a boolean value that indicates whether this is a primary service. If it
  is not a primary service, it is a secondary service.
Value
A boolean value.
Specifications
| Specification | 
|---|
| Web Bluetooth  # dom-bluetoothremotegattservice-isprimary  | 
Browser compatibility
BCD tables only load in the browser