Edit in JSFiddle

var people = {
    maxAge: 120,
    ages: [20, 30, 75, 156, 200],
    validAges: function () {
        return _.select(this.ages, function (age) {
            return age < this.maxAge;
        }, this);
    }
};

console.log(people.validAges());

              
            
          
            
              
                

              
            
          
            
              

External resources loaded into this fiddle: