/*

var book = {
 title : 'brave new world',
 author : 'aldous huxley',
 rating : '2' 
};

var params = {
 title : 'lmkwxlkc',
 author : 'ùsdfdlfmdlf',
 lkklk : 'lkkklmkkmlk',
 oppoip :'qlksdoieqsdls'
};


*/

var query = _.pick(params, _.keys(book));

/*

output :

query = {
 title : 'lmkwxlkc',
 author : 'ùsdfdlfmdlf'
};

*/