javascript-fundamentals 2

paperproblems/HOF/problem1.txt

@@ -7,6 +7,8 @@ Specifically:
  - What does it do?
 
 
+Filter is a function that takes two parameters. The first is an array, and the second is a function. The filter function goes through every element of the array and returns all elements in a new object that pass the second function's test. 
+
 
 var evenNumbers = [2, 4, 6, 8, 10];
 var oddNumbers = [3, 5, 7, 9];

paperproblems/HOF/problem2.txt

@@ -6,6 +6,9 @@ Specifically:
  - What are the types of the parameters
  - What does it do?
 
+
+Map is a function that takes two parakeets. The first is an array and the second is function. Map will pass each element in array to the function and return the results in a new array. 
+
 var someNumbers = [1, 2, 3, 4];
 var someStrings = ["bob", "ERIC"];
 

paperproblems/HOF/problem3.txt

@@ -8,4 +8,6 @@ function f(g) {
     return g(3,5);
 }
 
-console.log(f(k));
+console.log(f(k));
+
+15

paperproblems/HOF/problem4.txt

@@ -12,4 +12,8 @@ function f(g, h) {
     return g(h, 1, 4);
 }
 
-console.log(f(k, m));
+
+
+console.log(f(k, m));
+
+Nan

paperproblems/__proto__/problem1.txt

@@ -1,4 +1,4 @@
-Draw the object diagram for this program
+ Draw the object diagram for this program
 
 var x1 = {};
 var x2 = {};

paperproblems/__proto__/problem2.txt

@@ -9,9 +9,14 @@ x3.__proto__ = x2;
 x4.__proto__ = x3;
 
 x1.age = 20;
-x3.age = 18;
+x3.age = 18; 
 
 console.log(x1.age);
 console.log(x2.age);
 console.log(x3.age);
-console.log(x4.age);
+console.log(x4.age);
+
+20
+20
+18
+18

paperproblems/__proto__/problem3.txt

@@ -11,4 +11,6 @@ You get the following exception:
 
 
 a) Explain what this exception means.
-b) Why does this exception exist? What's wrong with a cyclic __proto__ value?
+b) Why does this exception exist? What's wrong with a cyclic __proto__ value?
+
+This is a cyclic __proto__ value because the proto of the object which a points to, is being pointed at the proto of b. B is pointing back proto of a, creating a loop that will never end. If you are looking for something in proto of a and it has been pointed at the proto of b b, it  then look in the proto of b, if there is nothing there, it would normally then go to the global proto and look there. If it couldn't find it there it would return an error. However if the proto of b is also pointing BACK at a, then it will continue looking forever, never reaching the global proto. 

paperproblems/anonymous-functions/problem1.txt

@@ -5,4 +5,13 @@ function greet(x) {
     console.log("hello " + x);
 }
 
-greet(bob);
+greet("bob");
+
+
+var greet = function(x){console.log("hello " +x);}
+
+(function(x) {console.log("hello" + x);})(bob);
+
+
+
+

paperproblems/anonymous-functions/problem2.txt

@@ -12,3 +12,11 @@ function call(f) {
 }
 
 call(greet);
+
+
+var greet = function(x){console.log("hello " + x);}
+
+var call = function(f){f("bob")}
+
+
+(function(f){f("bob");})(function(x){console.log("hello " + x);})

paperproblems/anonymous-functions/problem3.txt

@@ -10,3 +10,10 @@ function call(f) {
 }
 
 call(greet);
+
+
+var greet = function (x,y){console.log("hello" + x + " " + y);
+
+Var call = function (f){f("bob", "dole")};
+
+(function(f){f("bob", "dole");})(function(x,y){console.log("hello" + x + " " +y);})

paperproblems/anonymous-functions/problem4.txt

@@ -10,4 +10,11 @@ function twice(f) {
     f("mary");
 }
 
-twice(greet);
+twice(greet);
+
+Var twice = function (f){f("bob");f("Mary");}
+
+Var greet = function(x) {console.log("hello" + x);}
+
+(function(f){f("bob");f("Mary");})(function(x) {console.log("hello " + x);})
+

paperproblems/array-functions/problem1.txt

@@ -13,4 +13,6 @@ var dogs = animals.filter(
                 function(animal)
                      {return animal.species === 'dog';});
 
-console.log(dogs.length);
+console.log(dogs.length);
+
+2

paperproblems/array-functions/problem2.txt

@@ -13,4 +13,7 @@ var letterN = animals.filter(function(animal) {
     return animal.name !== undefined && animal.name[0] === 'N'
 });
 
-console.log(letterN[0].name);
+console.log(letterN[0].name);
+
+
+Nacho

paperproblems/array-functions/problem3.txt

@@ -10,4 +10,8 @@ var animals = [
 var animalNames = animals.map(
                     function(animal) {return animal.name});
 
-console.log(animalNames.join());
+console.log(animalNames.join());
+
+"Nacho,Ramses,Flufftail,Popcorn,Neckbeard," 
+
+// empty string takes a place in the array, but does not appear in the string exactly, but you know it's there because there is a comma after Neckbeard indicating that neckbeard is not the last element in the array. if the last name were undefined, it would look the same as it does here. 

paperproblems/array-functions/problem4.txt

@@ -11,8 +11,11 @@ function isDog(animal) {
     return animal.species === 'dog';
 }
 
-animals.some(isDog)
+animals.some(isDog) 
 animals.every(isDog)
 
 
+true
+false
+
 

paperproblems/arrow-functions/problem1.txt

@@ -4,16 +4,30 @@ For each of the following expressions:
 
 a) x => x + 1
 
+(no. Input numbers, output numbers)
+
 b) x, y => x * y
 
+Syntax error : if more than one parameter, parentheses required on parameters
+
 c) x => { x * 2 }
 
+(no. inputs number, output number )
+
 d) (x, z) => {console.log(z); return x * z}
 
+(no. inputs number, output number)
+
 e) x => console.log(z); return x * z
 
+(Syntax error. if more than one line of code, curly braces are required)
+
 f) (x) => x * 2
 
+(No, input number output number)
+
 e) () => console.log("hello")
 
+no.input? Output = string
+
 When you're done, check all your answers in the developer console.

paperproblems/callbacks/problem1.txt

@@ -12,4 +12,6 @@ function h() {
     setTimeout(f, 1000);
 }
 
-setTimeout(h, 200);
+setTimeout(h, 200);
+
+After 1700ms console.log hello

paperproblems/callbacks/problem2.txt

@@ -8,4 +8,6 @@ function h() {
     setInterval(g, 1000);
 }
 
-setInterval(h, 1000);
+setInterval(h, 1000);
+
+

paperproblems/classes/problem2.txt

@@ -12,11 +12,14 @@ class Person {
     }
     toString() {
         return "My name is " + this.name +
-          "and I'm " + this.age + " and I make " + this.salary;
+          " and I'm " + this.age + " and I make " + this.salary;
     }
 }
 
 var bob = new Person(25, "Bob", 40000);
 
 bob.increaseSalary(-500);
-console.log(bob.toString());
+console.log(bob.toString());
+
+"Yay!"
+"My name is Bob and I'm 25 and I make 39500"

paperproblems/conditional-operator/problem1.txt

@@ -4,4 +4,6 @@ function f(x) {
     return x < 5 ? 3 : x > 8 ? 4 : x == 6 ? 12 : 9;
 }
 
-console.log(f(5));
+console.log(f(5));
+
+9

paperproblems/constructor-functions/problem1.txt

@@ -1,7 +1,7 @@
 Draw the object diagram for the following program. 
 Hints: 
-  - There are two variables: makePerson and bob
-  - makePerson has a property called prototype
+  - There are two variables: Person and bob
+  - Person has a property called prototype
   - bob has properties constructor and __proto__
 
 function Person(name, age) {

paperproblems/constructor-functions/problem2.txt

@@ -12,4 +12,6 @@ var bob = new Person("Bob", 30);
 
 Person.prototype.leave = function() {return this.name + " is leaving";}
 
-bob.leave();
+bob.leave();
+
+Nothing - need a console.log to print "bob is leaving"

paperproblems/constructor-functions/problem3.txt

@@ -16,4 +16,7 @@ Person.prototype.salary = Person.prototype.salary + 300;
 Person.__proto__.salary = Person.__proto__.salary + 400;
 bob.salary = bob.salary + 50;
 
-console.log(bob.salary);
+console.log(bob.salary);
+
+
+40450

paperproblems/constructor-functions/problem4.txt

@@ -12,4 +12,6 @@ var bob = Person("Bob", 30);
 
 bob.name = bob.name + " Dole";
 
-bob.greet();
+bob.greet();
+
+error - need New in order to work, otherwise greet is not linked to bob. 

paperproblems/constructor-functions/problem5.txt

@@ -1,6 +1,5 @@
 Rewrite this program so that it does't use the new keyword.
 The program must be equivalent in every other way.
-(You would never do this in production. This is for learning purposes)
 
 function Person(name, age) {
     this.name = name;
@@ -11,4 +10,20 @@ function Person(name, age) {
 }
 
 var bob = new Person("Bob", 30);
-var sue = new Person("Sue", 24);
+
+//
+
+
+
+function Person(name, age){
+	var ret= {
+		name: name,
+		age: age,
+		greet: function (){console.log ("hello my name is " + this.name)}
+}ret.__proto__=Person.prototype;
+Return ret;
+}
+
+
+var bob = Person("bob", 30);
+

paperproblems/exceptions/problem1.txt

@@ -13,3 +13,5 @@ function g() {
 }
 
 g();
+
+500

paperproblems/exceptions/problem2.txt

@@ -23,3 +23,6 @@ function g() {
 }
 
 g();
+
+500
+"some error"

paperproblems/inheritance/problem2.txt

@@ -11,3 +11,19 @@ class Shape {
           this.area() + " and perimeter " + this.perimeter();
     }
 }
+
+class Rectangle extends Shape {
+	constructor(width, height){
+	super ('rectangle');	
+	this.width = width;
+	this.height = height;
+	}
+	area(){
+		return this.height * this.width
+		}
+	perimeter(){
+		return (this.height*2)+(this.width*2)
+		}
+}
+var rec = new Rectangle (3, 4);
+console.log(rec.toString());

paperproblems/return/problem1.txt

@@ -7,3 +7,6 @@ function f() {
 
 console.log(f());
 
+
+5
+

paperproblems/this/problem1.txt

@@ -9,3 +9,8 @@ function foo() {
 var obj = {bar: foo, baz: 8};
 obj.bar();
 
+8
+
+
+
+

paperproblems/this/problem2.txt

@@ -10,3 +10,5 @@ var obj = {
 var g = obj.bar;
 g();
 
+undefined
+