zoo.js

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

var Zoo = {

  init: function(animals){
    this.animals = animals
    this.two_legs = []
    this.four_legs = []
  },

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

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

 }
}

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

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

// console.log("Zoo = " + Zoo)

assert(
  Zoo.bipeds().length === 3, "the Zoo should have 3 bipeds"
  );
assert(
  Zoo.quadrupeds().length === 2, "the Zoo should have 2 quadrupeds"
  );
// console.log("animals[0] = " + animals[0].identify())
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"
  );