zoo.js

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

function Animal(name, num_legs) {
        this.name = species;
        this.num_legs = num_legs;        
    }

    Animal.prototype = {
        identify: function () {
            console.log("I am a "+this.name+" with "+this.num_legs+" legs");
        },
     };    


var Zoo = {

    init: function(animal_array){
      animals = animal_array;
    },

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

    quadrupeds: function(){
      var sum_quadrupeds = 0
    for (var i = 0; i < animals.length; i++){
      if (animals[i].num_legs === 4){
        sum_quadrupeds ++;
      }
    }
    return sum_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"
);