Terry edwards

README.md

@@ -26,14 +26,27 @@ Edit this document to include your answers after each question. Make sure to lea
 
 1. Briefly compare and contrast `.forEach` & `.map` (2-3 sentences max)
 
+.forEach and .map are both iterator functions that return arrays. While .forEach is mutable .map is imutable and returns a new array
+
 2. Explain the difference between a callback and a higher order function.
 
+A higher order function takes another function as an argument and returns a function to its callers but a callback passes itself to another function to be called upon by the said function
+
 3. What is closure?
 
+Closures give access to the outer scope of a function from the inner function.
+
 4. Describe the four rules of the 'this' keyword.
 
+  1. the global object binds "this" to the window object. 
+  2. implicit binding is when "this" refers to whats to the left of the dot when the dot calls a function.
+  3. new binding binds "this" to the instance of the object thats being created and returned by a constructor function.
+  4. explicit binding is when "this" is explicitly defined to bind "this" to an object by calling the constuctor object with .call and .apply.
+
 5. Why do we need super() in an extended class?
 
+Super() in an extended class  allow binding to acheive object inheritance by telling a parent constructor to be concerned with the child’s attributes.
+
 ### Task 1 - Project Set up
 
 Follow these steps to set up and work on your project:

challenges/arrays-callbacks.js

@@ -21,6 +21,8 @@ The zoos want to display both the scientific name and the animal name in front o
 
 */
 const displayNames = [];
+let display=zooAnimals.forEach((displays)=>{
+  displayNames.push(`Name: ${displays.animal_name}, Scientific: ${displays.scientific_name}`)})
 console.log(displayNames);
 
 /* Request 2: .map()
@@ -30,6 +32,7 @@ The zoos need a list of all their animal's names (animal_name only) converted to
 */
 
 const lowCaseAnimalNames = [];
+let lowAnimals=zooAnimals.map((names)=>lowCaseAnimalNames.push(names.animal_name.toLowerCase()))
 console.log(lowCaseAnimalNames);
 
 /* Request 3: .filter() 
@@ -38,15 +41,16 @@ The zoos are concerned about animals with a lower population count. Using filter
 
 */
 const lowPopulationAnimals = [];
+let lowPop=zooAnimals.filter((pop)=>{if(pop.population<5){lowPopulationAnimals.push(`Name- ${pop.animal_name}, Population- ${pop.population}`)}})
 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;
-console.log(populationTotal);
+const populationTotal=zooAnimals.reduce((total,finalPop)=>{return total+=finalPop.population;},0)
+console.log("The total animal population across the United States is "+populationTotal+" animals!");
 
 
 // ==== Callbacks ====  
@@ -57,19 +61,26 @@ console.log(populationTotal);
   * The last parameter accepts a callback
   * 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,cb){return(a+b)}
+
+function multiply(a,b,cb){return(a*b)}
+
+function greeting(a,b,cb){return(`Hello ${a} ${b}, 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!
 
 
 

challenges/classes.js

@@ -1,7 +1,26 @@
 // 1. Copy and paste your prototype in here and refactor into class syntax.
 
+class CuboidMaker{
+    constructor(length,width,height){
+    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))
+      }
+    }
+    class Cube extends CuboidMaker{
+        constructor(length, width, height){
+            super(length, width, height);
+        }}
+        const cuboid=new Cube(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.

challenges/closure.js

@@ -18,7 +18,16 @@ myFunction();
 
 // Explanation: 
 
+"The nested function can access the variable (internal) because they are both inside the (myFunction scope) and while you can't access a variable that is inside a closed function the function can pull variables from outside its scope."
 
 /* Task 2: Counter */
 
 /* Create a function called `sumation` that accepts a parameter and uses a counter to return the summation of that number. For example, `summation(4)` should return 10 because 1+2+3+4 is 10. */
+function sumation(x){
+  let sum=0;
+  for(let i=1;i<=x;i++){
+    sum+=i;
+  }
+  return(sum)
+}
+console.log(sumation(4));

challenges/prototypes.js

@@ -5,29 +5,45 @@
 /* == Step 1: Base Constructor ==
   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.   
 */
-
+// function Child(length,width,height){
+//   CuboidMaker.call(this,length,width,height);
+// }
+// Child.prototype=Object.create(CuboidMaker.prototype)
+// const cube = new Child({
+//   length:4, width:5, height:5,
+// });
+const cuboid= new CuboidMaker(length=4, width=5, height=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