zoo.js

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

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

var Zoo = {
  init: function(animals) {
    this.animals = animals;
  },
  bipeds: function(){
    var bi = this.animals.filter(function(animal) { return animal.legs == 2; });
    console.log(bi);
    return bi;
  },
  quadrupeds: function(){
    var quad = this.animals.filter(function(animal) { return animal.legs == 4; });
    console.log(quad);
    return quad;
  },
};

//------------------------------------------------------------------------------------------------------------------
// DRIVER CODE: Do **NOT** change anything below this point. Your task is to implement code above to make this work.
//------------------------------------------------------------------------------------------------------------------
//Success!
function assert(test, message) {  
  if (!test) {
    throw "ERROR: " + message;
  }
  return true;
}

//Success!
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)
];

//Success!
Zoo.init(animals);

//Success!
assert(
  Zoo.bipeds().length === 3, "the Zoo should have 3 bipeds"
);

//.............
assert(
  Zoo.quadrupeds().length === 2, "the Zoo should have 2 bipeds"
);

// Success! 
assert(
  animals[0].identify() === "I am a Human with 2 legs.", "humans have 2 legs"
);

// Success!
assert(
  animals[2].name === "Kangaroo", "expected 'Kangaroo'"
);

// Success!
assert(
  animals[0].identify === animals[5].identify, "only one implementation of the identify() function should exist"
);