JS Nested Sort Example (with comparator function factory for composing arbitrary nesting levels)

nestedSort.js

//some sample data for the example 
var people = [ {firstName: "Bob", lastName: "Barker", age: 100}, {firstName: "John", lastName: "Smith", age: 40}, {firstName: "Sam", lastName: "Adams", age: 42}, {firstName: "John", lastName: "Adams", age: 42}, {firstName: "Bernard", lastName: "Adams", age: 42}, {firstName: "Adam", lastName: "Adams", age: 42} ]; 

//generalized comparator function factory enabling composition with nested comparators 
var comparatorComposer = function(compareBy, nextComparator) { 
  var comparator = function(a, b) { 
      return ((a[compareBy] < b[compareBy]) ? -1 : ((a[compareBy] > b[compareBy]) ? 1 : (nextComparator ? nextComparator(a, b) : 0))); 
  }; 
  return comparator; 
}; 

//run each of these pairs of lines in the Chrome console to see the output 
var compareByFirstName = comparatorComposer("firstName"); 
people.sort(compareByFirstName); 

var compareByLastNameAndFirstName = comparatorComposer("lastName", compareByFirstName); 
people.sort(compareByLastNameAndFirstName); 

var compareByAgeAndLastNameAndFirstName = comparatorComposer("age", compareByLastNameAndFirstName); 
people.sort(compareByAgeAndLastNameAndFirstName);