Help concatenating values and send to a Device Status in Node Red

[goldriver]

I am exploring multiple routes to get the location from a iphone to my HomeRemote app. I used to work with PHLocation that is no more supported. I am now looking both the MQTT route and the node red route. as I am not a developer I am struggling a lot when comes time to do some programming so please bare with me.

I just installed Node-red and started playing with it and it seems to be an incredible power tool. I am trying to figure out how I can merge two values from a Node message and set a device status containing this cancatenated result.

I am able to update a device status using Node-red, I at least figured that out but my problem is to merge values. Let say I have the following Message coming out of a Node: (extracted from a debud node)

object

iPhone: array[1]

0: object

modelName: "iPhone 12 Pro"

deviceID: "/xyz="
displayName: "iPhone12"
batteryLevel: 82
batteryState: "NotCharging"
locationInfo: object
altitude: 0
latitude: 45.76989884492547
longitude: -74.11944542087066

locationTimeStamp: "2020-11-14 19:52"

refreshTimeStamp: "2020-11-14 19:53:42"

what would be the best way to create a msg.payload.status containing "latitude,longitude" ?

****** update *****
I found a way, may be not the best but it works, I added a function node with the following:

var lati1 = String(msg.payload.iPhone[0].locationInfo.latitude);
var long1 = String(msg.payload.iPhone[0].locationInfo.longitude);
msg.payload.status = lati1 + "," + long1;
return msg;

[ksum]

Function nodes should be your last resort. In your casr you can use a Change node and set the To field to be an Expression which users JSONata. The expression should be something such as

msg.payload.iPhone[0].locationInfo.latitude & ',' & msg.payload.iPhone[0].locationInfo.longitude

Use & to concatenate strings on a JSONata expression.


The Change node will look like this. I am using the Node Red editor Android app called RED Client Editor so the expression field is cut off.

[goldriver]

ksum thanks for this, just curious, why should function nodes be my last resort ?

[ksum]

The Function node runs in a pseudo vm environment and is therefor slower. Anything you can do with standard nodes is faster. Most of the veteran Node Red users will tell you to avoid it if possible.