underscore can do it

mappick.js

var some_json = [
  {
    id: 1,
    title: 'first_element',
    other: 'i dont need it',
  },
  {
    id: 2,
    title: 'secont_element',
    other: 'i dont need it',    
  }
];

_.map(some_json, function(e) {
  return _.pick(e, 'id', 'title');
});