处理数组中的空项 JavaScript

Question

Im using node red to put something together simply, I'm not really a js person so I'm struggling a bit.

I have to create this json payload. If for example VpidA : msg.payload.ChanStat.VpidA[0] is empty or undefined, is there a way i can put a default value in? I need to do this for potentially many more items and I think catch statement might be required? Although seems like it might get messy...thoughts?

 msg.payload = [{ measurement: "a box", fields: { Sync: parseInt(syncStatus), cCRC: parseInt(msg.payload.ChanStat.cCRC[0]), yCRC: parseInt(msg.payload.ChanStat.yCRC[0]), lineRate: msg.payload.ChanStat.LineRate[0], VpidA : msg.payload.ChanStat.VpidA[0] }, tags:{ host:"a box", input: msg.payload.ChanStat.ChanNum[0], type: "sdi" }, timestamp: new Date() }]; return msg;

i

Answer 1

You can test for the presence of variable with a simple if statement (assuming you are in a Function Node)

if (msg.payload.ChanStat.VpidA[0] == undefined){
   //do what ever needs doing if the property doesn't exist
}