N/search Module
Filter.operator
Property Description: Operator used for the search filter. This value is set with the search.Operator enum. The search.Operator enum contains the valid operator values for this property.
Type: string (read-only)
Supported Script Types: All script types For more information, see SuiteScript 2.0 Script Types.
Module: N/search Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=Filter.operator

// Code Example 1

//Add additional code

//...

var mySearchFilter = search.createFilter({

    name: 'entity',

    operator: search.Operator.ISEMPTY

});

log.debug({

    details: 'Operator Used: '

        + mySearchFilter.operator

    });

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_452460571288.html