The case is simple - I\'ve got a following object:
Object {1: false, 2: true, 3: false, 4: false, 5: false, 6: false, 7: false, 8: true, 12: false, 13: false, 14
This might be easier
result = _.chain(obj) .map(function(value, key){ return value?key:false; }) .filter(function(v){ return v }) .value();