zoo.js

//------------------------------------------------------------------------------------------------------------------
// YOUR CODE: Create your Zoo "object literal" and Animal "constructor" and "prototypes" here.
//------------------------------------------------------------------------------------------------------------------

var Zoo = {
  init: function(animals) {
    this.animals = animals;
  },

  bipeds: function() {
    return this.animals.filter(function(animal) {
      return animal.legs === 2;
    });
  },

  quadrupeds: function() {
    return this.animals.filter(function(animal) {
      return animal.legs === 4;
    });
  }
}


function Animal(name, legs) {
  this.name = name;
  this.legs = legs;
}

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");

zoo.rb

# //------------------------------------------------------------------------------------------------------------------
# // YOUR CODE: Create your Zoo "object literal" and Animal "constructor" and "prototypes" here.
# //------------------------------------------------------------------------------------------------------------------
class Animal
  attr_reader :name, :legs
  def initialize(name, legs)
    @name = name
    @legs = legs
  end

  def identify
    "I am a #{name} with #{legs} legs."
  end
end 

class Zoo
  attr_reader :bipeds, :quadrupeds
  def initialize(animals)
    @animals = animals
    @bipeds = []
    @quadrupeds = []
    @animals.map { |a| @bipeds << a if a.legs == 2 } 
    @animals.map { |a| @quadrupeds << a if a.legs == 4}
  end
end


# //------------------------------------------------------------------------------------------------------------------
# // DRIVER CODE: Do **NOT** change anything below this point. Your task is to implement code above to make this work.
# //------------------------------------------------------------------------------------------------------------------

animals = [ Animal.new("Human", 2), Animal.new("Monkey", 2), Animal.new("Kangaroo", 2), Animal.new("Horse", 4), Animal.new("Cow", 4), Animal.new("Centipede", 100) ]

def assert(test, message)
  puts "ERROR: " + message if test == true 
end


z = Zoo.new(animals)
assert( z.bipeds.length == 3, "the Zoo should have 3 bipeds")
assert( z.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");