Note
This Project has been forked to work under Angular 13.
ngx-mqtt 
This library isn't just a wrapper around MQTT.js for angular. It uses observables and takes care of subscription handling and message routing.
This means although you have the possibility of mqtt.js to use mqtt, mqtts, tcp, ssl, wx or wxs as the protocol in the client options, you can't, because this is a browser library where you can't conntect with something other than websockets. You also can't use key, cert and ca for the same reasons.
If you have any issues using this library, please visit it's homepage and look for similar issues in the issue tracker before you file a bug.