Advanced-JavaScript-Mini Completed

app.js

@@ -1,40 +1,76 @@
 /* The four rules for 'this';
 * in your own words. explain the four rules for the "this" keyword below.
-* 1. 
-* 2. 
-* 3. 
-* 4. 
+* 1. In the global scope, `this` referes to the `window` object.
+* 2. Whenever a function is called, the object preceeding the dot is the `this` scope
+* 3. When an object is being created, `this` refers to the instance of the object that will be returned
+* 4. When you use call/apply/bind, you specify the `this` scope for the function to execute in
 * write out a code example of each explanation above
 */
 
 // First Rule
+let bob = function() { console.log(this); return 'Bob' };
+  // Window {stop: function, open: function, alert: function, confirm: function, prompt: function…}
+  // "Bob"
 
 // Second Rule
+class Fruit {
+  constructor(type, color) {
+    this.getType = function() { return type };
+    this.getColor = () => color;
+  }
+  message() {
+    console.log(this);
+    return `I am a ${this.getColor()} ${this.getType()}`; 
+  }
+}
+
+const apple = new Fruit("Apple", "Red");
+apple.message();
+  // Fruit {getType: function, getColor: function}
+  // "I am a Red Apple"
 
 // Third Rule
+// `this` in the Fruit class above is referencing `apple` during `apple`'s creation
 
 // Fourth Rule * you may want to use your third rule's example to accomplish this
+const orange = new Fruit("Orange", "Orange");
+let fruitMessage = apple.message;
+console.log(fruitMessage.call(orange));
+  // I am a Orange Orange
+console.log(fruitMessage.apply(orange));
+  // I am a Orange Orange
+fruitMessage = apple.message.bind(orange);
+console.log(fruitMessage());
+  // I am a Orange Orange
+
+
+// explain closure
+ // closure is a way for a function to hold onto an object created outside of it's
+ // scope even when that object normally would've been deleted as nothing
+ // would've been able to access it if it wasn't for that function
 
-// explain closure 
 
 function foo () {
   console.log(this); // what does this point to?
+  // `this` points to `window` because a new object isn't being created and
+  // foo is in the global scope.
 };
 
 const counterFunction = () => {
   // this code is broken. figure out why, and tell us where the closure is when you fix it
+  let count = 0; 
   const changeCount = (value) => {
-    count += value;
+    count += value; //closure is here. it is holding onto count
   };
   return {
     increment: () => {
-      changeCount(1);
+      changeCount(1); //closure is here. It is holding onto changeCount
     },
-    decrement: () => {
-      changeCount(-1);
+    decrement: () => { 
+      changeCount(-1); //closure is here. It is holding onto changeCount
     },
     total: () => {
-      return count;
+      return count; //closure is here. It is holding onto count
     }
   }
 };
@@ -53,15 +89,37 @@ console.log(counter.total());
   // assign these properties you pass in with options to the constructors 'this' object.
   // add a speak() method to your object that when called will log out the car's make model and year.
 
-// when you're done un comment the next few lines and run the file here in node `node app.js`.
+function Car(options) {
+  this.make = options.make;
+  this.model = options.model;
+  this.year = options.year;
+  this.speak = function() {
+    return `${this.year} ${this.make} ${this.model}`;
+  }
+}
 
-// const herby = new Car({make: 'Volkswagen', model: 'Beetle', year: '1963'});
-// console.log(herby.speak());
-// const goldfinger = new Car({make: 'Aston Martin', model: 'DB5', year: '1964'});
-// console.log(goldfinger.speak());
+const herby = new Car({make: 'Volkswagen', model: 'Beetle', year: '1963'});
+console.log(herby.speak());
+const goldfinger = new Car({make: 'Aston Martin', model: 'DB5', year: '1964'});
+console.log(goldfinger.speak());
 
 
 // once you get done with this, redo it all using the class keyword and a constructor function. 
+class Car {
+  constructor(options) {
+    this.make = options.make;
+    this.model = options.model;
+    this.year = options.year;
+  }
+  speak() {
+    return `${this.year} ${this.make} ${this.model}`; 
+  }
+}
+
+const herby = new Car({make: 'Volkswagen', model: 'Beetle', year: '1963'});
+console.log(herby.speak());
+const goldfinger = new Car({make: 'Aston Martin', model: 'DB5', year: '1964'});
+console.log(goldfinger.speak());
 
 // extra credit
 
@@ -75,6 +133,14 @@ while(n >= 1) {
 }
 // write a function called countDown that does the exact same thing as above, but calls itself until it can't anymore.
   // hint-> your base case will look like the logic in the while loop.
+const countDown = (n) => {
+  if(n > 0){
+    console.log(n);
+    countDown(--n);
+  }
+};
+
+countDown(10);