diff --git a/README.md b/README.md
index cc6d6902fb..668425bee9 100644
--- a/README.md
+++ b/README.md
@@ -25,15 +25,18 @@ Demonstrate your understanding of this week's concepts by answering the followin
Edit this document to include your answers after each question. Make sure to leave a blank line above and below your answer so it is clear and easy to read by your team lead
1. Briefly compare and contrast `.forEach` & `.map` (2-3 sentences max)
-
+.forEach does not put a new array into memory, .map does
2. Explain the difference between a callback and a higher order function.
-
+a callback invokes a higher-order function
3. What is closure?
-
+a function and what it can remember
4. Describe the four rules of the 'this' keyword.
-
+in the global scope refers to the window object.
+in implicit binding- when caled in a function represents the object preceding the dot
+in explicit binding-refers to the .call or .apply method
+in new binding refers to the specific instance in a constructor
5. Why do we need super() in an extended class?
-
+it replaes the .call and .apply methods
### Task 1 - Project Set up
Follow these steps to set up and work on your project:
diff --git a/challenges/arrays-callbacks.js b/challenges/arrays-callbacks.js
index 472ab3e96d..6f8e841fcd 100644
--- a/challenges/arrays-callbacks.js
+++ b/challenges/arrays-callbacks.js
@@ -20,7 +20,10 @@ const zooAnimals = [
The zoos want to display both the scientific name and the animal name in front of the habitats. Populate the displayNames array with only the animal_name and scientific_name of each animal. displayNames will be an array of strings, and each string should follow this pattern: "Name: Jackal, asiatic, Scientific: Canis aureus."
*/
-const displayNames = [];
+const displayNames = []
+zooAnimals.forEach((name) => {
+ displayNames.push(`animal_name: ${name.animal_name}, scientific_name: ${name.scientific_name}.`);
+})
console.log(displayNames);
/* Request 2: .map()
@@ -30,6 +33,9 @@ The zoos need a list of all their animal's names (animal_name only) converted to
*/
const lowCaseAnimalNames = [];
+ zooAnimals.map((name) => {
+ lowCaseAnimalNames.push( name.animal_name.toLowerCase());
+});
console.log(lowCaseAnimalNames);
/* Request 3: .filter()
@@ -37,15 +43,18 @@ console.log(lowCaseAnimalNames);
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((data) => {
+ return data.population > 6
+});
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.reduce((total,animal) => total + animal.population,0);
+
console.log(populationTotal);
@@ -57,19 +66,31 @@ 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(cb1,cb2){
+ return cb1 + cb2;
+};
+function multiply(cb1,cb2){
+ return cb1*cb2;
+};
+function greeting(cb1,cb2){
+ return `Hello ${cb1.toLowerCase()} ${cb2.toUpperCase()}, 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!
diff --git a/challenges/classes.js b/challenges/classes.js
index 992e39dc0b..2d7c9fd72e 100644
--- a/challenges/classes.js
+++ b/challenges/classes.js
@@ -1,7 +1,34 @@
// 1. Copy and paste your prototype in here and refactor into class syntax.
+class CircleMaker {
+ constructor(diameter) {
+ this.diameter = diameter;
+ }
+ area() {
+ return Math.PI * Math.pow((this.diameter / 2), 2);
+ }
+ circumference() {
+ return 2 * Math.PI * (this.diameter / 2);
+ }
+}
+
+
+const circle = new CircleMaker(5);
// Test your volume and surfaceArea methods by uncommenting the logs below:
-// console.log(cuboid.volume()); // 100
-// console.log(cuboid.surfaceArea()); // 130
+class SphereMaker extends CircleMaker {
+ constructor(diameter) {
+ super(diameter);
+ }
+ volume() {
+ return 4 / 3 * Math.PI * Math.pow(this.diameter / 2, 3);
+ }
+ area() {
+ return 4 * Math.PI * Math.pow(this.diameter / 2, 2);
+ }
+}
+
+const sphere = new SphereMaker(5);
+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.
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diff --git a/challenges/closure.js b/challenges/closure.js
index 101d68e553..e951f8a7d6 100644
--- a/challenges/closure.js
+++ b/challenges/closure.js
@@ -16,9 +16,21 @@ function myFunction() {
}
myFunction();
-// Explanation:
+// Explanation: Because a funcction that is nested within can see out but another function cannot see in.
/* 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(num){
+ let counter = 1;
+ return function() {
+ for(num; num > 1; num--) {
+ counter = counter + num
+ }
+ return counter;
+ }
+};
+const addition = sumation(4);
+
+console.log(addition());
\ No newline at end of file
diff --git a/challenges/prototypes.js b/challenges/prototypes.js
index 4cafc33e95..d90c790c77 100644
--- a/challenges/prototypes.js
+++ b/challenges/prototypes.js
@@ -4,7 +4,11 @@
/* == 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 ==
@@ -12,22 +16,23 @@
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.
*/
-
+const 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());
\ No newline at end of file