zoo.js

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

}

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


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

  bipeds: function(){
    var bipeds = [];
    for (var i = 0; i < this.animals.length; i++) {
      if (animals[i].legs ==2){
        bipeds.push(animals[i]);
      };
    };
    return bipeds;
  },

  quadrupeds: function(){
    var quadrupeds = [];
    for (var i = 0; i < this.animals.length; i++) {
      if (animals[i].legs ==4){
        quadrupeds.push(animals[i]);
      };
    };
    return quadrupeds;
  }

}



//------------------------------------------------------------------------------------------------------------------
// 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"
);