How to use flow variabile without modifing it

General
1

Hi all, can anyone explain to me why the flow's variable created with the first inject node is modified in the other two without using the flow.set() method?

[{"id":"26a58557.18feca","type":"inject","z":"938038fa.b84288","name":"Make a flow variable","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"IdDispositivo\":8,\"SystemGroup\":\"OLCIS\",\"IP\":\"192.168.1.132\",\"ShutdownDelay\":\"0\"}","payloadType":"json","x":170,"y":100,"wires":[["9a5d3c3a.80b9f"]]},{"id":"c566479c.b8dae8","type":"function","z":"938038fa.b84288","name":"setFlow.DeviceToPayload","func":"let x = flow.get('device')||0;\nlet payload = x;\npayload.count = 0;\nreturn {payload};","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":190,"y":400,"wires":[[]]},{"id":"9a5d3c3a.80b9f","type":"change","z":"938038fa.b84288","name":"","rules":[{"t":"set","p":"device","pt":"flow","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":180,"y":160,"wires":[[]]},{"id":"a3defa86.57a188","type":"inject","z":"938038fa.b84288","name":"take flow variable to use it in the msg without modifing flow variable","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"true","payloadType":"bool","x":280,"y":220,"wires":[["72dde4c6.6c969c"]]},{"id":"72dde4c6.6c969c","type":"change","z":"938038fa.b84288","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"device","tot":"flow"},{"t":"set","p":"payload.count","pt":"msg","to":"0","tot":"num"}],"action":"","property":"","from":"","to":"","reg":false,"x":160,"y":280,"wires":[[]]},{"id":"6560276b.544388","type":"inject","z":"938038fa.b84288","name":"Do the some but in a function","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"true","payloadType":"bool","x":160,"y":340,"wires":[["c566479c.b8dae8"]]}]
2

Because JS objects are copied and stored by reference

Clone the message
https://nodered.org/docs/api/modules/v/1.3/@node-red_util_util.html

let x = flow.get('device')||0;
let payload = RED.util.cloneMessage(x);
payload.count = 0;
return {payload};
1 Like
3

image
OK! I got it
now ther's a new problem

4

My fault typo on "Red" should be "RED"

1 Like
5

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