Here is how I populate a dashboard table with hostname and IP address of Linux devices alive on my network. It may be applicable to your list of sensors.
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{} // get data from context\ndevices = sortObj(devices) // Sort it by key (IP address)\n\nlet arr = [] // Will pass an array of objects to the table\nconst now = new Date().getTime()\n\nfor (let ip in devices) { // Loop through sensors\n const age = (now - devices[ip].timestamp.getTime())/1000 // Age in seconds of the sensor report - can use to id stale records\n let rec = { // Construct object for this sensor\n \"ip\": ip,\n \"hostname\": devices[ip].hostname,\n // etc, etc\n }\n arr.push(rec) // Add it to the array\n}\n\nmsg.payload = arr;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":320,"y":240,"wires":[["28a4d3149680d07f"]]},{"id":"28a4d3149680d07f","type":"ui_table","z":"90fe1578c260fc2b","g":"733fb7b343c1f04d","group":"a29767e44538ea22","name":"Table ","order":0,"width":"9","height":"6","columns":[],"outputs":0,"cts":false,"x":490,"y":240,"wires":[]},{"id":"a29767e44538ea22","type":"ui_group","name":"Pies","tab":"75458084fdb19d21","order":1,"disp":false,"width":"30","collapse":false,"className":""},{"id":"75458084fdb19d21","type":"ui_tab","name":"Status","icon":"dashboard","disabled":false,"hidden":false}]
I don't use a join node, each incoming mqtt message is added/updated discretely in a context variable.
My context variable is an object keyed by IP address rather than an array, so I can sort the data by IP.
ps. I don't actually know if I need to sort the context variable, maybe it will automatically come out in alphabetical order of the key?
-)
icon.
