Import set transform map should not overwrite target field if source field value is '##' (in example)

[Anders Pr_stega]

Hi

I have an import process that uses an attached Excel-file as source. I can then replace that Excel-file to implement changes on demand. As of now "Copy empty fields" is enabled on the transform map, which is fine, but I now need to provide a means to bypass "copy empty fields"  in some cases.

I had the idea that I could simply replace the empty field with a fixed code (ie '##') and then change the field map to a scripted field and do the following:

answer = (function transformEntry(source) {
// Add your code here
if(source.u_asset_tag == '##'){
ignore = true;
}
else{
return source.u_asset_tag;
}
})(source);

 To my surprise this does not prevent the field from an update, as itøs if target.asset_tag is just passed null or an empty string resulting in the value "Undefined".

Some thoughts: How is the "target" dictionary  affected for a record when "Copy empty fields" is NOT enabled. Is the attribute removed from the target table behind the scenes, to prevent the field from being overwritten with a blanc value?

[Anders Pr_stega]

Update:

I've fiddled around with this new approach, that could have some potential:

(function runTransformScript(source, map, log, target /*undefined onStart*/ ) {	
	if(action == "update") {
		for (var property in source){
			var targetProperty = property.replace('u_','');
			if (source[property] == '##'){
				gs.log('DEBUG Source property ' + property + ' contains ' + source[property]);
				gs.log('DEBUG Target property ' + targetProperty + ' contains ' + target[targetProperty]);
				delete source[property];
				//_.omit(source,property);
			}
		}
	}
})(source, map, log, target);

The logs in the center of the code works as expected and only when the input has the ## in it.

The line "delete source[property];" does not work unfortunately. I wonder if the source input variable is read-only (as per the documentation the map input variable is read-only).