OldField,NewField,Shown,Language,Mapping
Field1,anotherfield,,,
Field2,PreviousField1,,Javascript,"return previousLine.isEmpty() ? ""no-previous"" : ""found-previous"" + previousLine.get(outputHeaders.indexOf(""anotherfield""));"
,PreviousMappedField2,,Javascript,"return previousMappedLine.isEmpty() ? ""no-map-previous"" : ""found-map-previous"" + columnFunction(""PreviousField1"", outputHeaders, previousMappedLine);"

OldField,NewField,Shown,Language,Mapping
Field1,anotherfield,,,
Field2,PreviousField1,,Javascript,"return previousLine.isEmpty() ? ""no-previous"" : ""found-previous"" + previousLine.get(inputHeaders.indexOf(""Field1""));"
,PreviousMappedField2,,Javascript,"return previousMappedLine.isEmpty() ? ""no-map-previous"" : ""found-map-previous"" + columnFunction(""PreviousField1"", outputHeaders, previousMappedLine);"

Fix semantic error, need to be using the input field on previousLine
Fix semantic error, need to be using the input field on previousLine