I would like to implement correct nodered way of joining messages. There are 4 droplists and elements can be selected from all 4 independent from each other. After selection is finished, button in dashboard is pressed.
I usually join with flow.set() but decided it is a time to learn something new
Feed the button into the Join node too, with the node in key/value mode, and the inputs each having different topics. Set And Every Subsequent Message in the node so that it passes on a message for every input. Then add a Switch node after the join node which only passes messages with the submit button topic. So every time you press the button you will get a message with all the values.