lib/base.js
function cleanup(a) {
      return _.filter(a, function (a) {
        var field = a[0];
        return attr[field];
      });
    }
function cleanup(a) {
      return _.filter(a, function (a) {
        var field = a[0];
        return attr[field];
      });
    }
function cleanup ( a ) { return _ . filter ( a , function ( a ) { var field = a [ 0 ] ; return attr [ field ] ; } ) ; }
drop all fields that aren't found in the attributes array
drop all fields that aren t found in the attributes array