zoo.js

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

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

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