Input for device node should support msg.payload as action parameter

[mwittig]

Currently, the device node tries to read msg.parameter if the Parameter field is left empty. In my opinion, the node should (also) support to use msg.payload instead as otherwise a transformation must be added each time when the device is used as part of a flow chain with other nodes, e.g. dashboard UI items:

Suggested alternatives for fixture:

• Use msg.payload instead of msg.parameter, i.e., replace msg.paramter with msg.payload in the code OR
• Add an option, e.g. checkbox, to use msg.payload.

For the latter I have drafted an implementation which perhaps is not yet perfect as I am still a beginner with the node-red API. I can push it to a seperate branch if you wish to review. See: https://github.com/mwittig/pimatic-node-red/commit/e05701b63f4a0bfe7066dd02f8e41d5362c39361

[joshendriks]

This makes sense. I do not recall why I decided to use msg.parameter in the first place. Maybe it will pop up ...

I think it should be built in a way that the user may choose which value to take. Similar to 'Output' on the debug node:

Default should be msg.parameter for backwards compatibility. The option to provide a value should remain.

What do you think?