zoo.js

//------------------------------------------------------------------------------------------------------------------
// YOUR CODE: Create your Zoo "object literal" and Animal "constructor" and "prototypes" here.
//------------------------------------------------------------------------------------------------------------------
  var Zoo = {
    init: function (){},
    bipeds: function (){
      var array = []
      for ( var i = 0; i<animals.length; i++) {
        if (animals[i].legs === 2) {
          array.push(animals[i])
        }
      }
      return array
    },
    quadrupeds: function (){
      var array = []
      for ( var i = 0; i<animals.length; i++) {
        if (animals[i].legs === 4) {
          array.push(animals[i])
        }
      }
      return array    }
  }

  var Animal = function(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"
);