MarkRivera · MarkRivera · Feb 22, 2020 · Feb 22, 2020 · Feb 22, 2020 · Feb 22, 2020
diff --git a/README.md b/README.md
@@ -30,14 +30,27 @@ Edit this document to include your answers after each question. Make sure to lea
 
 1. Describe the biggest difference between `.forEach` & `.map`.
 
+    .map() returns a new array of elements after completion while .forEach() returns undefined.
+
 2. What is the difference between a function and a method?
 
+    A method is a function which belongs to an object. Functions do not necessarily need to belong to any object.
+
 3. What is closure?
 
+    It's an enclosed space where rules govern which data can be accessed or how it is accessed. For example, when you declare a function it creates its own local scope where data is exclusive to that function only. So if a varible is created within that function, nothing outside of that function can 'read' that data unless it is returned from the function explicitly.
+
 4. Describe the four rules of the 'this' keyword.
 
+    A. This will refer to the window/global object if not implicitly or explicitly binded.
+    B. this will be binded to the object which a method was called from. (Implicit binding)
+    C. When using constructors, this will be binded to what ever object was created using the new keyword.
+    D. You can explicitly bind this using any of these methods: .bind(), .call(), .apply()
+
 5. Why do we need super() in an extended class?
 
+    super() is the equivalent of Obj.prototype = Object.create(Person.prototype). In essence it makes the child constructor aware of the parent prototype.
+
 ## Project Set up
 
 Follow these steps to set up and work on your project:

diff --git a/challenges/classes.js b/challenges/classes.js
@@ -1,7 +1,44 @@
 // 1. Copy and paste your prototype in here and refactor into class syntax.
 
+class CuboidMaker {
+    constructor(length, height, width){
+        this.length = length;
+        this.width = width;
+        this.height = height;
+    }
+
+    volume() {
+        return this.length * this.width * this.height;
+    }
+
+    surfaceArea() {
+        return 2 * (this.length * this.width + this.length * this.height + this.width * this.height);
+    }
+}
+
+let cuboid = new CuboidMaker(4, 5, 5);
+
 // Test your volume and surfaceArea methods by uncommenting the logs below:
-// console.log(cuboid.volume()); // 100
-// console.log(cuboid.surfaceArea()); // 130
+console.log(cuboid.volume()); // 100
+console.log(cuboid.surfaceArea()); // 130
+
+// Stretch Task: Extend the base class CuboidMaker with a sub class called CubeMaker.  Find out the formulas for volume and surface area for cubes and create those methods using the dimension properties from CuboidMaker.  Test your work by logging out your volume and surface area.
+
+class CubeMaker extends CuboidMaker {
+    constructor(length, width, height) {
+        super(length, width, height);
+    }
+
+    volume() {
+        return this.length * this.width * this.height
+    }
+
+    surfaceArea() {
+        return 6 * (this.length * this.width);
+    }
+}
+
+let cube = new CubeMaker(5, 5, 5);
 
-// Stretch Task: Extend the base class CuboidMaker with a sub class called CubeMaker.  Find out the formulas for volume and surface area for cubes and create those methods using the dimension properties from CuboidMaker.  Test your work by logging out your volume and surface area.
+console.log(cube.volume()); // 125
+console.log(cube.surfaceArea()); // 150
diff --git a/challenges/functions.js b/challenges/functions.js
@@ -7,18 +7,33 @@
   * The consume function should return the invocation of cb, passing a and b into cb as arguments
 */
 
+function consume(a, b, cb) {
+  return cb(a, b);
+}
+
 
 /* Step 2: Create several functions to callback with consume();
   * Create a function named add that returns the sum of two numbers
   * Create a function named multiply that returns the product of two numbers 
   * Create a function named greeting that accepts a first and last name and returns "Hello first-name last-name, nice to meet you!"
 */
 
+function add(a, b) {
+    return a + b;
+}
+
+function multiply(a, b) {
+  return a * b;
+}
+
+function greeting(first, last) {
+  return `Hello ${first} ${last}, nice to meet you!`;
+}
 
 /* Step 3: Check your work by un-commenting the following calls to consume(): */
-// console.log(consume(2, 2, add)); // 4
-// console.log(consume(10, 16, multiply)); // 160
-// console.log(consume("Mary", "Poppins", greeting)); // Hello Mary Poppins, nice to meet you!
+console.log(consume(2, 2, add)); // 4
+console.log(consume(10, 16, multiply)); // 160
+console.log(consume("Mary", "Poppins", greeting)); // Hello Mary Poppins, nice to meet you!
 
 
 // ==== Closures ==== 
@@ -27,6 +42,12 @@
 
 // Explanation: 
 
+/* 
+
+  Javascript will begin looking for the variable internal within the nestedFunction's scope. However since it does not exist there, Javascript realizes that nestedFunction is a part of the outside function's scope and will move "one level up" to search for the variable. Since it does exist within myFunction's closure, it will access that variable. Javascript cannot move "one level down" as it is not allowed.
+
+*/
+
 
 const external = "I'm outside the function";
 

diff --git a/challenges/objects-arrays.js b/challenges/objects-arrays.js
@@ -8,27 +8,52 @@
 
 // tyrannosaurus, carnivorous, 7000kg, 12m, Late Cretaceous
 
+let tyrannosaurus = {
+  name: "Tyrannosaurus",
+  diet: "Carnivorous",
+  weight: "7000kg",
+  length: "12m",
+  period: "Late Cretaceous"
+}
+
 // stegosaurus, herbivorous, 2000kg, 9m, Late Jurassic
 
+let stegosaurus = {
+  name: "Stegosaurus",
+  diet: "Herbivorous",
+  weight: "2000kg",
+  length: "9m",
+  period: "Late Jurassic"
+}
+
 // velociraptor, carnivorous, 15kg, 1.8m, Late Cretaceous
 
+let velociraptor = {
+  name: "Velociraptor",
+  diet: "Carnivorous",
+  weight: "15kg",
+  length: "1.8m",
+  period: "Late Cretaceous"
+}
+
 // Using your dinosaur objects, log answers to these questions:
 
 // How much did tyrannosaurus weigh?
-console.log();
+console.log(tyrannosaurus.weight);
 
 // What was the diet of a velociraptor?
-console.log();
+console.log(velociraptor.diet);
 
 // How long was a stegosaurus?
-console.log();
+console.log(stegosaurus.length);
 
 // What time period did tyrannosaurus live in?
-console.log();
+console.log(tyrannosaurus.period);
 
 
 // Create a new roar method for the tyrannosaurus.  When called, return "RAWERSRARARWERSARARARRRR!" Log the result.
-console.log();
+tyrannosaurus.roar = function() { return "RAWERSRARARWERSARARARRRR!" };
+console.log(tyrannosaurus.roar());
 
 
 // ==== Arrays ====
@@ -51,7 +76,12 @@ const graduates = [
 /* Request 1: Create a new array called universities that contains all the universities in the graduates array. This will be an array of strings.
 
 Once you have the new array created, sort the universities alphabetically and log the result. */
-const universities = [];
+const unis = graduates.map(item => {
+  return item.university
+});
+
+let universities = unis.sort();
+
 console.log(universities);
 
 /* Request 2: Create a new array called contactInfo that contains both first name and email of each student. This will be an array of strings.
@@ -60,11 +90,18 @@ The resulting contact information strings should have a space between the first
 "Josh [email protected]"
 
 Log the result of your new array. */
-const contactInfo = [];
+const contactInfo = graduates.map(item => {
+  return `${item.first_name} ${item.email}`
+});
+
 console.log(contactInfo);
 
 /* Request 3: Find out how many universities have the string "Uni" included in their name. Create a new array called unisWithUni that contains them all. This will be an array of objects. Log the result. */
-const unisWithUni = [];
+const unisWithUni = graduates.filter(item => {
+  let uni = item.university.includes("Uni");
+  return uni && item
+});
+
 console.log(unisWithUni);
 
 
@@ -91,6 +128,12 @@ The zoos want to display both the scientific name and the animal name in front o
 
 */
 const displayNames = [];
+
+zooAnimals.forEach(element => {
+  let string = `Name: ${element.animal_name}, Scientific: ${element.scientific_name}.`;
+  displayNames.push(string);
+});
+
 console.log(displayNames);
 
 /* Request 2: .map()
@@ -99,23 +142,24 @@ The zoos need a list of all their animal's names (animal_name only) converted to
 
 */
 
-const lowCaseAnimalNames = [];
+const lowCaseAnimalNames = zooAnimals.map(element => element.animal_name.toLowerCase());
 console.log(lowCaseAnimalNames);
 
 /* Request 3: .filter() 
 
 The zoos are concerned about animals with a lower population count. Using filter, create a new array of objects called lowPopulationAnimals which contains only the animals with a population less than 5.
 
 */
-const lowPopulationAnimals = [];
+const lowPopulationAnimals = zooAnimals.filter(element => element.population < 5 && element);
 console.log(lowPopulationAnimals);
 
 /* Request 4: .reduce() 
 
 The zoos need to know their total animal population across the United States. Find the total population from all the zoos using the .reduce() method. Remember the reduce method takes two arguments: a callback (which itself takes two args), and an initial value for the count.
 
 */
-const populationTotal = 0;
+const populationTotal = zooAnimals.map(element => element.population).reduce((acc,current) => acc + current, 0);
+
 console.log(populationTotal);
 
 

diff --git a/challenges/prototypes.js b/challenges/prototypes.js
@@ -6,28 +6,44 @@
   Create a constructor function named CuboidMaker that accepts properties for length, width, and height
 */
 
+function CuboidMaker(length, width, height) {
+  this.length = length;
+  this.width = width;
+  this.height = height;
+}
+
 
 /* == Step 2: Volume Method ==
   Create a method using CuboidMaker's prototype that returns the volume of a given cuboid's length, width, and height
 
   Formula for cuboid volume: length * width * height
 */
 
+CuboidMaker.prototype.volume = function () {
+  return this.length * this.width * this.height;
+}
+
 
 /* == Step 3: Surface Area Method ==
   Create another method using CuboidMaker's prototype that returns the surface area of a given cuboid's length, width, and height. 
 
   Formula for cuboid surface area of a cube: 2 * (length * width + length * height + width * height)
 */
 
+CuboidMaker.prototype.surfaceArea = function() {
+  return 2 * (this.length * this.width + this.length * this.height + this.width * this.height);
+}
+
 
 /* == Step 4: Create a new object that uses CuboidMaker ==
   Create a cuboid object that uses the new keyword to use our CuboidMaker constructor
   Add properties and values of length: 4, width: 5, and height: 5 to cuboid.   
 */
 
+let cuboid = new CuboidMaker(4, 5, 5);
+
 // Test your volume and surfaceArea methods by uncommenting the logs below:
-// console.log(cuboid.volume()); // 100
-// console.log(cuboid.surfaceArea()); // 130
+console.log(cuboid.volume()); // 100
+console.log(cuboid.surfaceArea()); // 130
 
 
diff --git a/package-lock.json b/package-lock.json