JourdanClark · Sep 8, 2017 · Sep 11, 2017 · ryan-hamblin · Sep 12, 2017 · ryan-hamblin
diff --git a/notes/inheritance.js b/notes/inheritance.js
@@ -0,0 +1,135 @@
+/**
+  Let's say we have a class Monster. This class will define all of our Monsters at a generic level.
+  It will hold attributes that each Monster, be it a Zombie, a Skeleton, a Banshee, etc should have.
+**/
+class Monster {
+  constructor(name, hitpoints, level, inventory, nickname) {
+    this.name = name;
+    this.hitpoints = hitpoints;
+    this.level = level;
+    this.inventory = inventory || [];
+    this.nickname = nickname;
+  }
+  getDisplayName() {
+    return this.nickname || this.name; //if no nickname was provided, nickname will be undefined so name will be returned.
+  }
+  onAttack() {
+    console.log(`${this.getDisplayName()} attacked for 1 damage.`);
+  }
+  onDamage() {
+    console.log(`${this.getDisplayName()} took ${this.hitpoints - --this.hitpoints} damage!`);
+    if (this.hitpoints <= 0) {
+      this.onDeath();
+    }
+  }
+  onDeath() {
+    console.log(`${this.getDisplayName()} died!`);
+    if(this.inventory.length > 0) {
+      console.log(`${this.getDisplayName()} dropped: `);
+      this.inventory.forEach((item) => console.log(`\t${item}`));
+    } else {
+      console.log(`${this.getDisplayName()} didn't drop anything :(`);
+    }
+  }
+}
+
+/**
+  We now have the basic features a monster should have as well as default onAttack and onDamage methods that will apply to any
+  Monsters that don't come with their own. Lets create our different Monsters and extend the Monster class so they all get these features.
+**/
+class Zombie extends Monster {
+  constructor(stats) {
+    // You call `super` which calls Monster's constructor and lets Zombie inherit everything from Monster
+    super("Zombie", stats.hitpoints, stats.level, stats.inventory || ['sword'], stats.nickname);
+    this.rotten = 'hella';
+  }
+}
+
+class Skeleton extends Monster {
+  constructor(hitpoints, level, inventory = ["bow"], nickname) {
+    // You call `super` which calls Monster's constructor and lets Skeleton inherit everything from Monster
+    super("Skeleton", hitpoints, level, inventory, nickname);
+  }
+}
+
+class Banshee extends Monster {
+  constructor(hitpoints, level, inventory = undefined, nickname) {
+    // You call `super` which calls Monster's constructor and lets Banshee inherit everything from Monster
+    super("Banshee", hitpoints, level, inventory, nickname);
+  }
+  onAttack() {
+    this.scream();
+    // even though we are making our own onAttack method, we can still call the one from super
+    super.onAttack();
+  }
+  scream() {
+    console.log("AHHHHHH!!!!")
+  }
+}
+
+// Set up our dope battle simulator right here
+function battle(mon1, mon2) {
+  if(Math.random() >= 0.5) {
+    mon1.onAttack();
+    mon2.onDamage();
+  } else {
+    mon2.onAttack();
+    mon1.onDamage();
+  }
+}
+
+// Now we make some Monsters
+const zombie = new Zombie({hitpoints: 5, level: 3});
+const skeleton = new Skeleton(5, 3);
+const banshee = new Banshee(10, 3);
+const fred = new Zombie({hitpoints: 1, level: 1, nickname: "Fred"});
+const jill = new Banshee(2000, 1000, inventory = ['The God Staff of Omar Illingisisisisisisi', 'The Magic School Bus Season 1 Collectors Edition'], "Hillary, Joe's Mom");
+
+while (zombie.hitpoints > 0 && skeleton.hitpoints > 0) {
+  battle(skeleton, zombie);
+  console.log(" ");
+}
+
+while (fred.hitpoints > 0 && banshee.hitpoints > 0) {
+  battle(fred, banshee);
+  console.log(" ");
+}
+
+while (banshee.hitpoints > 0 && jill.hitpoints > 0) {
+ battle(banshee, jill);
+ console.log(" ");
+}
+
+console.log(" ");
+console.log("He has risin! Oh glorious Fred, may he bring glory to the heavens and rain fire on all those who appose him!!!");
+console.log(" ");
+console.log(" ");
+
+fred.hitpoints = 200000;
+fred.level = 9000+1;
+fred.inventory.push('The God Staff of Omar Illingisisisisisisi +2');
+
+fred.scream = function() {
+  console.log("Ooooga Boooggggaaa!!");
+}
+
+fred.onAttack = function() {
+  this.scream();
+  console.log(`${this.getDisplayName()} attacked for !@#!$%@#~! damage.`);
+  jill.hitpoints = -100000;
+}
+
+while (fred.hitpoints > 0 && jill.hitpoints > 0) {
+  battle(fred, jill);
+  console.log(" ");
+}
+
+// Some further tests to show how these interact
+console.log(`typeof zombie: ${typeof zombie}`);
+console.log(`zombie instanceof Zombie: ${zombie instanceof Zombie}`);
+console.log(`zombie instanceof Monster: ${zombie instanceof Monster}`);
+console.log(`zombie instanceof Skeleton: ${zombie instanceof Skeleton}`);
+console.log(`zombie instanceof Banshee: ${zombie instanceof Banshee}`);
+console.log(`typeof zombie === typeof skeleton: ${typeof zombie === typeof skeleton}`);
+console.log(`typeof zombie === typeof fred: ${typeof zombie === typeof fred}`);
+// console.log(`zombie instanceof fred: ${zombie instanceof fred}`); //error because fred isn't a class/constructor.
diff --git a/notes/this-scope.js b/notes/this-scope.js
@@ -0,0 +1,57 @@
+class Fruit{
+  constructor(type, color){
+    this.getType = function(){return type};
+    this.getColor = () => color;
+  }
+}
+
+const apple = new Fruit("Apple", "Red");
+
+// Fruit.prototype.message = () => `I am a ${this.getColor()} ${this.getType()}`;
+// console.log(apple.message());
+/**
+  Uncaught TypeError: this.getColor is not a function
+    at Fruit.message (<anonymous>:10:48)
+    at <anonymous>:12:19
+**/
+
+Fruit.prototype.message = function() {
+  return `I am a ${this.getColor()} ${this.getType()}`;
+};
+
+console.log(apple.message());
+/**
+  I am a Red Apple
+**/
+
+const orange = new Fruit("Orange", "Orange");
+
+let fruitMessage = apple.message;
+
+console.log(fruitMessage);
+// [Function]
+
+console.log(fruitMessage.call(orange));
+// I am a Orange Orange
+console.log(fruitMessage.apply(orange));
+// I am a Orange Orange
+
+// console.log(fruitMessage());
+/** TypeError: this.getColor is not a function
+  `this` is evaluated when the code is run rather than when
+  the object is created. By calling fruitMessage() in this way,
+  you have taken apple.message out of apple's scope and moved it
+  into the global scope. `this.getColor()` is now looking for `getColor()`
+  in the global scope which is undefined.
+**/
+
+fruitMessage = apple.message.bind(orange);
+/** bind doesn't execute the function
+  it hold onto it and will apply the `this` scope when you call it later
+**/
+
+console.log(fruitMessage);
+// [Function]
+
+console.log(fruitMessage());
+// I am a Orange Orange!
diff --git a/src/arrays.js b/src/arrays.js
@@ -8,33 +8,67 @@ const each = (elements, cb) => {
   // Iterates over a list of elements, yielding each in turn to the `cb` function.
   // This only needs to work with arrays.
   // based off http://underscorejs.org/#each
+  for (let i = 0; i < elements.length; i++) {
+    cb(elements[i], i);
+  }
 };
 
 const map = (elements, cb) => {
   // Produces a new array of values by mapping each value in list through a transformation function (iteratee).
   // Return the new array.
+  const arr = [];
+  each(elements, (item, index) => { arr.push(cb(item, index)); });
+  return arr;
 };
 
 const reduce = (elements, cb, memo = elements.shift()) => {
   // Combine all elements into a single value going from left to right.
   // Elements will be passed one by one into `cb`.
   // `memo` is the starting value.  If `memo` is undefined then make `elements[0]` the initial value.
+  if (typeof memo === 'undefined') {
+    memo = elements[0];
+  }
+  each(elements, (item, index) => { memo = cb(memo, item, index); });
+  return memo;
 };
 
 const find = (elements, cb) => {
   // Look through each value in `elements` and pass each element to `cb`.
   // If `cb` returns `true` then return that element.
   // Return `undefined` if no elements pass the truth test.
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i])) {
+      return elements[i];
+    }
+  }
+  return undefined;
 };
 
 const filter = (elements, cb) => {
   // Similar to `find` but you will return an array of all elements that passed the truth test
   // Return an empty array if no elements pass the truth test
+  const array = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i])) {
+      array.push(elements[i]);
+    }
+  }
+  return array;
 };
 
 const flatten = (elements) => {
   // Flattens a nested array (the nesting can be to any depth).
   // Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
+  const array = [];
+  const cb = (item) => {
+    if (item instanceof Array) {
+      each(item, cb);
+    } else {
+      array.push(item);
+    }
+  };
+  each(elements, cb);
+  return array;
 };
 
 /* eslint-enable no-unused-vars, max-len */

diff --git a/src/class.js b/src/class.js
@@ -5,7 +5,17 @@
 // Add a method called `comparePasswords`.  `comparePasswords` should have a parameter
 // for a potential password that will be compared to the `password` property.
 // Return true if the potential password matches the `password` property.  Otherwise return false.
+const arrayMethods = require('../src/arrays');
 
+class User {
+  constructor(options) {
+    this.email = options.email;
+    this.password = options.password;
+  }
+  comparePasswords(compare) {
+    return this.password === compare;
+  }
+}
 
 /* eslint-disable no-undef */ // Remove this comment once you write your classes.
 
@@ -18,7 +28,24 @@
 // Cat should have the property `name` that is set in the constructor and the method
 // `meow` that should return the string `<name> meowed!` where `<name>` is the `name`
 // property set on the Cat instance.
+class Animal {
+  constructor(options) {
+    this.age = options.age;
+  }
+  growOlder() {
+    return ++this.age;
+  }
+}
 
+class Cat extends Animal {
+  constructor(options) {
+    super(options);
+    this.name = options.name;
+  }
+  meow() {
+    return `${this.name} meowed!`;
+  }
+}
 
 module.exports = {
   User,

diff --git a/src/closure.js b/src/closure.js
@@ -1,21 +1,32 @@
 // Complete the following functions.
+const arrayMethods = require('../src/arrays');
 
 const counter = () => {
   // Return a function that when invoked increments and returns a counter variable.
   // Example: const newCounter = counter();
   // newCounter(); // 1
   // newCounter(); // 2
+  let c = 0;
+  return () => ++c;
 };
 
 const counterFactory = () => {
   // Return an object that has two methods called `increment` and `decrement`.
   // `increment` should increment a counter variable in closure scope and return it.
   // `decrement` should decrement the counter variable and return it.
+  let c = 0;
+  return { increment: () => ++c, decrement: () => --c };
 };
 
 const limitFunctionCallCount = (cb, n) => {
   // Should return a function that invokes `cb`.
   // The returned function should only allow `cb` to be invoked `n` times.
+  return (...rest) => {
+    if (n-- > 0) {
+      return cb(...rest);
+    }
+    return null;
+  };
 };
 
 const cacheFunction = (cb) => {
@@ -25,6 +36,13 @@ const cacheFunction = (cb) => {
   // If the returned function is invoked with arguments that it has already seen
   // then it should return the cached result and not invoke `cb` again.
   // `cb` should only ever be invoked once for a given set of arguments.
+  const cache = {};
+  return (arg) => {
+    if (!(arg in cache)) {
+      cache[arg] = cb(arg);
+    }
+    return cache[arg];
+  };
 };
 
 /* eslint-enable no-unused-vars */