FYI, in configuration.yaml, change the "friendly_name"'s to something that is "friendly", then you will receive the friendly names in node-red (restart zigbee2mqtt once done), you don't have to parse the yaml file.
First connect a debug node to the zigbee mqtt node, set the output to "complete msg object" and post the output here. The reason why you get the "Failed to parse JSON string" errors is because the debug node is set to display the msg.payload. The mqtt node however, outputs strings of data, hence the error.
It worked yesterday! And today it's writes an error: "TypeError: Cannot read property 'length' of undefined"
I just in configuration.yaml, changed the "friendly_name" and rebooted.
my "new" configuration.yaml
Thanks for the answer! I will keep in mind for the next time then I will rename my devices.
now I returned to yesterday's value i.e. to the original default name.
And still doesn't work!
And yes i see that the error comes from the “update chart” node. But, this knowledge does not help me!
That flow seems to be setup in an odd way.
I would delete all nodes and start from scratch to start learning node-red.
Start with the mqtt node and a debug node, determine the data you receive and after that, watch all the videos in this playlist to get an understanding of node-red and how it works.