Sorting array of custom objects in JavaScript

Question

Say I have an array of Employee Objects:

var Employee = function(fname, age) {
    this.fname = fname;
    this.age = age;
}

var employees = [
    new Emplo         


        

Answer 1

I provide my own sortBy method for arrays that lets you specify an arbitrary number of fields to sort by, using a Schwartzian transform:

Example 1

var a=[ {c:"GK",age:37}, {c:"ZK",age:13}, {c:"TK",age:14}, {c:"AK",age:13} ];

a.sortBy( function(){ return this.age } );                                   
// [ {c:"ZK",age:13}, {c:"AK",age:13}, {c:"TK",age:14}, {c:"GK",age:37} ] 

a.sortBy( function(){ return [this.age,this.c] } );                          
// [ {c:"AK",age:13}, {c:"ZK",age:13}, {c:"TK",age:14}, {c:"GK",age:37} ] 

a.sortBy( function(){ return -this.age } );                                  
// [ {c:"GK",age:37}, {c:"TK",age:14}, {c:"ZK",age:13}, {c:"AK",age:13} ] 

Example 2:

var n=[ 1, 99, 15, "2", "100", 3, 34, "foo", "bar" ];                        

n.sort();                                                                    
// [ 1, "100", 15, "2", 3, 34, 99, "bar", "foo" ]                         

n.sortBy( function(){ return this*1 } );                                     
// [ "foo", "bar", 1, "2", 3, 15, 34, 99, "100" ]                         

n.sortBy( function(o){ return [typeof o,this] } );                           
// [1, 3, 15, 34, 99, "100", "2", "bar", "foo"]                           

n.sortBy(function(o){ return [typeof o, typeof o=="string" ? o.length : o] })
// [1, 3, 15, 34, 99, "2", "100", "bar", "foo"]                           

The Code

(function(){
  // This code is copyright 2012 by Gavin Kistner, !@phrogz.net
  // License: http://phrogz.net/JS/_ReuseLicense.txt
  if (typeof Object.defineProperty === 'function'){
    try{Object.defineProperty(Array.prototype,'sortBy',{value:sb}); }catch(e){}
  }
  if (!Array.prototype.sortBy) Array.prototype.sortBy = sb;

  function sb(f){
    for (var i=this.length;i;){
      var o = this[--i];
      this[i] = [].concat(f.call(o,o,i),o);
    }
    this.sort(function(a,b){
      for (var i=0,len=a.length;i