zoo.js

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

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

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

Zoo = 
{
    animals: animals,
    init: function(animals) 
        {
        this.animals = animals;
        },
    bipeds: function() 
    {
    var bipeds = [];
    for (var i = 0; i < this.animals.length; i+= 1) 
        {
            if (animals[i].legs==2)
            {
            bipeds.push(animals[i]);
            }
        }
    return bipeds;
},

  quadrupeds: function() 
  {
     var quadrupeds = [];
      for (var i = 0; i < this.animals.length; i+= 1) 
      {
        if (animals[i].legs ==4)
        {
          quadrupeds.push(animals[i]);
        }
      }
      return quadrupeds;
  }
}
// Zoo.bipeds= ["Human","Monkey","Kangaroo"]
// Zoo.quadrapeds = ["Horse","Cow"]
// Zoo.bipeds = function() {this.twolegs}




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