How check undefined msg in a function node?

General
6

@zenofmud yes, i tried but the error is coming when msg.payload[0] is undefined and not when have a value. I don't find an all in one solution.

To be clearer I enter the full code:

if (msg.payload[0] != "undefined"){

   if (msg.payload[0].r_id > 0 && msg.payload[0].r_id != "undefined"){

        let formatobject = [{ "Nessuno": 0 }];

        for (let i = 0; i < msg.payload.length; i++) {

            let tempnome = msg.payload[i].r_nome;

            let tempid = msg.payload[i].r_id;

            let tempobject = {};

            tempobject[tempnome] = tempid;

            formatobject.push(tempobject);

        }

        msg1.options = formatobject;

        node.send([msg1, null, null, null, null, null, null]);

   }

}