zoo.js

//------------------------------------------------------------------------------------------------------------------
// YOUR CODE: Create your Zoo "object literal" and Animal "constructor" and "prototypes" here.
//------------------------------------------------------------------------------------------------------------------
var Animal = function(name, legs){
  this.name = name;
  this.legs = legs;
}

var Zoo = {
  content: [],

  init:  function(array){
    this.content =  this.content.concat(array);
  },

  animals_with_legs: function(number_of_legs){
    return this.content.filter(function(animal){ return animal.legs == number_of_legs})

  },

  bipeds: function(){
    return this.animals_with_legs(2);
  },

  quadrupeds:  function(){
    return this.animals_with_legs(4);
  }
}




Animal.prototype.identify = function(){
    return "I am a " + this.name + " with " + this.legs + " legs."
}

//------------------------------------------------------------------------------------------------------------------
// DRIVER CODE: Do **NOT** change anything below this point. Your task is to implement code above to make this work.
//------------------------------------------------------------------------------------------------------------------
 
function assert(test, message) {  
  if (!test) {
    throw "ERROR: " + message;
  }
  return true;
}
 
var animals = [
  new Animal("Human", 2),
  new Animal("Monkey", 2),
  new Animal("Kangaroo", 2),
  new Animal("Horse", 4),
  new Animal("Cow", 4),
  new Animal("Centipede", 100)
];
 
Zoo.init(animals);
 
assert(
  Zoo.bipeds().length === 3, "the Zoo should have 3 bipeds"
);
assert(
  Zoo.quadrupeds().length === 2, "the Zoo should have 2 bipeds"
);
assert(
  animals[0].identify() === "I am a Human with 2 legs.", "humans have 2 legs"
);
assert(
  animals[2].name === "Kangaroo", "expected 'Kangaroo'"
);
assert(
  animals[0].identify === animals[5].identify, "only one implementation of the identify() function should exist"
);

zoo2.js

//------------------------------------------------------------------------------------------------------------------
// YOUR CODE: Create your Zoo "object literal" and Animal "constructor" and "prototypes" here.
//------------------------------------------------------------------------------------------------------------------
var Animal = function(name, legs){
  this.name = name;
  this.legs = legs;
}

var ZooClass = function(){
  var content = [];

  this.init= function(array){
    content = content.concat(array);
  };

  function animals_with_legs(number_of_legs){
    return content.filter(function(animal){ return animal.legs == number_of_legs})

  }
  this.bipeds = function(){
    return animals_with_legs(2);
  };

  this.quadrupeds = function(){
    return animals_with_legs(4);
  }
}

 Zoo = new ZooClass;


Animal.prototype.identify = function(){
    return "I am a " + this.name + " with " + this.legs + " legs."
}

//------------------------------------------------------------------------------------------------------------------
// DRIVER CODE: Do **NOT** change anything below this point. Your task is to implement code above to make this work.
//------------------------------------------------------------------------------------------------------------------
 
function assert(test, message) {  
  if (!test) {
    throw "ERROR: " + message;
  }
  return true;
}
 
var animals = [
  new Animal("Human", 2),
  new Animal("Monkey", 2),
  new Animal("Kangaroo", 2),
  new Animal("Horse", 4),
  new Animal("Cow", 4),
  new Animal("Centipede", 100)
];
 
Zoo.init(animals);
 
assert(
  Zoo.bipeds().length === 3, "the Zoo should have 3 bipeds"
);
assert(
  Zoo.quadrupeds().length === 2, "the Zoo should have 2 bipeds"
);
assert(
  animals[0].identify() === "I am a Human with 2 legs.", "humans have 2 legs"
);
assert(
  animals[2].name === "Kangaroo", "expected 'Kangaroo'"
);
assert(
  animals[0].identify === animals[5].identify, "only one implementation of the identify() function should exist"
);