I am working on a project - top secret just now. 
This is the code in the function node.
let j = flow.get("StartMsg");
if (j == undefined)
{
j = "Start message";
}
msg.payload = j;
if (flow.get("PassThrough" == true))
{
msg.payload = flow.get("SavedMessage");
}
return msg;
But it throws up this error:
TypeError: key.startsWith is not a function
Where is this happening?
I don't get it. Sorry.
It is the last condition that is doing it.
if (flow.get("PassThrough" == true)) that is causing it to the best of my knowledge.