var cities = [{
name: 'Name 1',
city: 'city 1',
developer: 'dev 1',
},
{
name: 'Name 2',
city: 'city 2',
developer: 'dev 2',
},
{
name: 'Name 3',
city: 'city 1',
developer: 'dev 3',
}];
var result = _.uniqBy(cities, 'city');
console.log(result);