Netsuite Suitescript Api - Searching Transaction Records Returns Duplicates

I am attempting a basic search query of the 'transaction' records (I have also attempted this with 'salesorder' with similar results). The query has no filters, and requests only

Solution 1:

Please add a filter,

mainline is TRUE

If you are using saved search via code, please add additional filter

as new nlobjSearchFilter('mainline', null, 'is', 'T') or ['mainline', 'is', 'T']

as the search result pull up the same internal id, multiple times for all line items

EDIT: For the provided code example

var columns = [];
columns.push(new nlobjSearchColumn('internalid'));

var searchResults = nlapiSearchRecord('transaction', null, ['mainline', 'is', 'T'], columns);   

return searchResults;