Uncaught SyntaxError: Unexpected token 'if'

i'm New in Javascript

Code :-

$('#similar-artist').append('<div class="chip" data-uuid="'+ item.artist_id +'" >'+ item.name  + '  ' + if (item.last_name){ item.last_name }else{}  +'</div>');

Errore :- Uncaught SyntaxError: Unexpected token 'if'

Thank You