Hi,

how the value is present in the incoming data i.e. import set table; you can use field map script for this; choice action as ignore

Note: ensure you compare proper values in if condition with the incoming values; also use proper source field

I believe it should be u_priority and not priority

answer = (function transformEntry(source) {

	// Add your code here
var targetValue = '';	

var sourcePriority = source.u_priority;
if(sourcePriority == 'High')
targetValue = 1;
else if(sourcePriority == 'Medium')
targetValue = 2;
else if(sourcePriority == 'Low')
targetValue = 3;


})(source);

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Thanks
Ankur