SFMC SSJS error handling - try catch

Question

I have the following code:

<script runat="server">

Platform.Load("Core","1.1.1");

try{
    var logDE = DataExtension.Init("testDE");

    throw "this is an error";

    logDE.Rows.Add({"c1":"success"});
} 

catch(e)
{
    logDE.Rows.Add({"c1":e});
}
</script>

I run this inside Automation Studio. However, it should throw an error and use the catch block.

The catch block will add a row to the DE "testDE" with "this is an error".

This is my theory, but I just get an error during execution without any information of why.

To rule out any issues with the DE I have removed the throw and the DE is populating with "success".

Why is my catch block not working?

Answer 1

Variables declared in the try block context cannot be accessed in the catch block. So even though the exception is caught, there is an error in the catch block.

try {
    var a = 1;
    throw 'myException';
} catch(e) {
    Platform.Response.Write(a);   
    // exception is caught and output is "undefined" 
}

You can either init your DE again inside the catch block or move the variable declaration outside the try block.

var logDE = DataExtension.Init("testDE");
try{
    throw "this is an error";
    logDE.Rows.Add({"c1":"success"});
} catch(e) {
    logDE.Rows.Add({"c1":e});
}