Create Objects from List object (global context)

General
1

Trying to create a list of Mixers objects in the Global Context and set the MixerID property as defined in List object. Objects are defined as:

//Mixer Object definition
    var MixerUDT = {
                    "MixerID" : "",
                     "Speed_SP":0, 
                     "Speed_PV":0, 
                     "Direction":0, 
                     "Comms_OK":1, 
                     "Comms_Sent_ID":0,
                     "Comms_Retires":0,
                     "Comms_Errors" :0 
                     }


    //List of Mixer to create including their ID
    var MixerList = {
                     "M01": "Mixer01",
                     "M02": "Mixer02" 
                     }

Looking for help with code to iterate through MixerList to create mixers M01 & M02 and set their MixerIDs to "Mixer01" and "Mixer02" respectively...Alternatively, help debugging any one of the approaches I've tried below:

All approaches I've tried create Mixers object with correct names, but the MixerID for all mixers is the same: "Mixer02". Cannot for the life of me work out why.
Suspect it has something to do with not understanding when pass-by-references versus pass-by-value is occurring!

APPROACH 1:

//For each Key in  MixerList create a MixerUDT and set MixerID
    for ( let KeyName in MixerList) {
        MixerUDT.MixerID = MixerList[KeyName];   //set MixerID in UDT 
        global.set(KeyName.toString(),MixerUDT); //create instance in global context

        //For Diagnostics
        msg.payload = MixerUDT;         //In each iteration I see MixerUDT has been correctly updated
        node.send(msg);
    }

APPROACH 2:

 //For each Key in  MixerList create a MixerUDT and set MixerID
    for ( let KeyName in MixerList) {
        global.set(KeyName.toString(),MixerUDT);   //create instance of default UDT

        let _Mixer = global.get(KeyName.toString()); //get reference to global variable?!
        _Mixer["MixerID"] = MixerList[KeyName];      //change the MixerID

        //For Diagnostics
        msg.payload = _Mixer;         //In each iteration I see _Mixer has been correct updated
        node.send(msg);
        }

Thanks in advance.

3

You are setting references to the same object each time. You need to clone it.

Try

const clone= {...MixerUDT}
clone.name = KeyName
global.set(KeyName.toString(), clone)
1 Like
4

Thanks for helping out a NOOB, Steve.

Is the line const clone= {...MixerUDT} pseudo code?!
I'm not familiar with "{..."

Also, I should use:

clone.MixerID = KeyName;
5

No. This is JavaScript. The ... is the spread (or rest) operator. It works on arrays and objects.

6

If you need to debug you can use node.warn for point in time values.

E.g.

node.warn({clone})

This will output to the node-red debug sidebar

7

You're a champ. Thank you.

8

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