var test_data = [ { firstName: 'Rob', lastName: 'Tweed', city: 'Redhill', gender: 'Male' }, { firstName: 'Simon', lastName: 'Tweed', city: 'St Albans', gender: 'Male' }, { firstName: 'Susanne', lastName: 'Salling', city: 'Redhill', gender: 'Female' }, { firstName:...