Suggestions for Level 2 (#4)

* Suggestions for Level 2

* fixup! Suggestions for Level 2

Author: ajhyndman

js/level2.js

@@ -1,93 +1,143 @@
-//Level2
+// Level2
 
 /*
-  Now, when we start level2, it is time to interact with html file. HTML files is a structure
-  of our web-page - a skeleton. It combines all files from the project together, that is how
-  it know what to do. If you check on our index.html file on the bottom you will see tag
-  <script src="js/level1js"></script> - that is where we joined our first js file. But now
-  change level1.js file on our current one - level2.js.
-  Now you are ready to start!
+    Introduction
+    ============
+
+    Welcome to level 2! It is time to interact with HTML.
+
+    Hyper Text Markup Language (HTML) files are the backbone of the internet.
+    Every website you visit is loaded first as an HTML file.
+
+    We won't talk too much about HTML today. What you need to know is that HTML
+    files function as a sort of skeleton for your page. Our index.html file
+    combines all the files from this project together so that you can open them
+    in your web browser.
+
+    This project has a file called index.html. At the bottom of index.html you
+    will see the following tag:
+
+    <script src="js/level1.js"></script>
+
+    That is how you have been running the level1.js file. Now change level1.js
+    to this file — level2.js.
+
+    Now you are ready to start!
  */
 
-/* Arrays
-    It is an ordered list of values. It can keep any number of values inside. And also
-    any type of values - numbers, strings, objects.
+/*
+    Arrays
+    ======
+
+    An array is an ordered list of values. It can keep any number of values
+    inside. And also any type of values — numbers, strings, objects.
+
     Example:
+
     var animals = ['cat', 'dog', 'horse];
     var randomThings = [2, 'book', 'today is Saturday', 10];
     var numbers = [1, 2, 8, 19];
  */
 
-//TODO: create your own array named favouriteFood and write in couple of things you like.
+// TODO: Create your own array, named favouriteFood, and write in a couple of
+// things you like.
+
 
 
 
 
+/*
+    Array Length
+    ============
+
+    We can easily check how many items we have in our array with a property:
+    '.length'
 
-/* Array length
-    We can easily check how many items we have in our array with property '.length'
     Example:
     var randomThings = [2, 'book', 'today is Saturday', 10];
-    console.log(randomThings.length); //we will get 4
+    console.log(randomThings.length); // we will get 4
  */
 
-//TODO: check up on how many values you have in your array favouriteFood and console.log it
+// TODO: Check up on how many values you have in your array favouriteFood.
+// console.log the result.
+
+
 
 
 
 
+/*
+    Array Usage
+    ===========
+
+    It's useful to keep all of these values in one place. But what if we want
+    to use only 1 item from the array?
 
+    We can get them out using 'bracket notation'. Thanks to a guy named Edsger
+    Dijkstra*, array indices start counting from 0. Usage looks like this.
 
-/* Arrays usage
-    So, it is comfortable to keep all this values in one place, but what if we want to use
-    only 1 item from the array, we can get them out using 'bracket notation'.
-    As all counting in programming starts with 0, the first element in the array will have
-    position 0 etc
     Example:
+
     var randomThings = [2, 'book', 'today is Saturday', 10];
     var firstItem = randomThings[0];
     var secondItem = randomThings[1]; and so on
+
+    * https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD831.html
  */
 
-//TODO: get 3rd element from your array favouriteFood and console.log it
+// TODO: Get third element from your array favouriteFood and console.log it.
 
 
 
 
 
 
 
-/* Changing values in arrays
-    We also can replace values inside of the arrays by assigning specific item from
-    the array to a new value.
+/*
+    Changing Values in Arrays
+    =========================
+
+    We also can replace values inside of the arrays by assigning a new value to
+    a specific index.
+
     Example:
+
     var animals = ['cat', 'dog', 'horse'];
-    //let's replace 'dog' with 'fish'
+
+    // let's replace 'dog' with 'fish'
     animals[1] = 'fish';
-    //now our animals array will be ['cat', 'fish', 'horse']
+
+    // now our animals array will be ['cat', 'fish', 'horse']
  */
 
-//TODO: take your array favouriteFood and replace first value with anything else.
-//console.log whole array to check
-// Dont forget, that index position starts with 0
+// TODO: take your array favouriteFood and replace first value with anything
+// else.
+// console.log whole array to check
+// Dont forget, index positions start from 0!
+
+
 
 
 
 
 
+/*
+    Array.push()
+    ============
 
+    If you want to add new values to an existing array you can use the method
+    '.push()'. Push will add a new value to the end of the array.
 
-/* Adding values to array
-    If you want to add new value to array you can use property of array named '.push'.
-    It will add value to the end of the array
     Example:
+
     var animals = ['cat', 'dog', 'horse'];
     animals.push('rabbit');
-    so now our array will be ['cat', 'dog', 'horse','rabbit']
+
+    // animals will be ['cat', 'dog', 'horse','rabbit']
  */
 
-//TODO: let's extend your list of favouriteFood and add one more value in it.
-//console.log list of your favouriteFood and check
+// TODO: let's extend your list of favouriteFood and add one more value in it.
+// console.log list of your favouriteFood and check
 
 
 
@@ -96,35 +146,55 @@
 
 
 
-/* Loops
-    People always have been lazy and it was moving progress forward. We don't like to repeat
-    same boring actions again and again, so we are looking for ways how to improve it.
-    Programming is the same - for example, if I want to print 'JavaScript is awesome!' 10
-    times what are my options? Of course, I can print 10 lines of code repeating same
-    phrase over and over again, but I also can tell computer to repeat it instead of me.
+/*
+    Loops
+    =====
+
+    People have always been lazy, but sometimes it moves progress forward! We
+    don't like to repeat the same boring actions again and again, so we look
+    for ways to avoid it.
+
+    Programming is the same. For example, if I want to print 'JavaScript is
+    awesome!' 10 times, what are my options? Of course, I can type ten lines of
+    code repeating the same instruction, but I can also tell the computer to
+    repeat it instead of me!
+
     For this we have loops.
-    Each loop should have 3 main things:
+
+    Each loop should have three main things:
     - starting point
     - condition (finishing point)
     - counter (a step)
-    If you miss one of them you can get into infinite loop!!!
 
-    Let's look into different looping structures
+    If you miss one of these, you can get into an infinite loop!
+
+    Let's look into different looping structures.
  */
 
 
-/* While loops
-  'While' loop will do the action over and over again untill
-  some condition will be met.
-  For example:
-  var number = 0;   //starting point
-  while (number < 10) {      //10 is a condition/finishing point
-    console.log('JavaScript is awesome!');
-    number = number + 1;          // + 1 is a counter/size of the step
-  }
+/*
+    While Loops
+    ===========
+
+    'While' loop will do an action forever until some condition is met.
+
+    Example:
+
+    // starting point
+    var number = 0;
+
+    while (number < 10) {
+      // 'less than 10'' is a condition (finishing point)
+
+      console.log('JavaScript is awesome!');
+
+      number = number + 1;
+      // + 1 is a counter/size of the step
+    }
  */
 
-//TODO: Using 'while loop' tell your computer to print you numbers from 10 to 1
+// TODO: Using a 'while loop', tell your computer to log the numbers from
+// ten to one.
 
 
 
@@ -133,35 +203,48 @@
 
 
 
-/* For loops
-    'For loop' is very similar to 'while loop', but you declare a counter in the statement.
-    For example:
-    for(var i = 0; i <= 5; i++){  //(starting point, condition, step)
+/*
+    For Loops
+    =========
+
+    'For loop's are very similar to the 'while loop'. In a for loop, you
+    declare a counter in the statement.
+
+    Example:
+
+    var i;
+    for (i = 0; i <= 5; i = i + 1) {  // (starting point; condition; step)
       console.log('Purr');
     }
-    PS: i++ is a short from 'i = i + 1'
  */
 
-//TODO: now, let's print every 3rd number from 3 to 22 using 'for loop'
+// TODO: Log every 3rd number from three to 22 using a 'for loop'.
+
 
 
 
 
 
 
+/*
+    Iterating Through Arrays
+    ========================
+
+    Now we know about loops. I want to use each value from my animal list
+    and express my love for each. How shall I do it?
+
+    We can use a 'for loop' to iterate through our array and get each value
+    from it.
 
-/* Iterating through arrays
-    Now, when we know about loops I want to use each value from my animal
-    list and say that I love all of those animals, how shall I do it?
-    We can use 'for loop' to iterate through our array and get each value from it.
     Example:
+
     var animals = ['cats', 'dogs', 'horses];
     for(var i = 0; i < animals.length; i++){
-      console.log('I love ' + animals[i]);
+        console.log('I love ' + animals[i]);
     }
  */
 
-//TODO: try it out with your list of favouriteFood that you created before.
+// TODO: Try it out with your favouriteFood array.
 
 
 
@@ -173,27 +256,42 @@
 
 
 
-/* Loops and Logic
-    Now, when we know about if/else statements and loops let's combine them together
-    and make something more interesting. Let's count from 10 to 0 and print all the
-    numbers, but when we get to the middle(5) print ''WooHoo, we are in the middle'.
+/*
+    Loops and Logic
+    ===============
+
+    Let's bring loops together with the if/else statements we learned in
+    level 1, and make something interesting.
+
+    Let's count from 10 to 0 and log all the numbers. But, when we get to the
+    middle (5) print 'Woohoo, we are in the middle!'.
+
     Example:
-    for(var i = 10; i > 0; i--){
-      if(i == 5){
-        console.log('WooHoo, we are in the middle');
-      } else {
-        console.log(i);
-      }
+
+    for (var i = 10; i >= 0; i = i - 1) {
+        if (i === 5) {
+            console.log('WooHoo, we are in the middle!');
+        } else {
+            console.log(i);
+        }
     }
  */
 
-//TODO: Time has come for a classic exercise - 'FizzBuzz'. Count from 1 to 50 and print
-// numbers out. If number is a multiple of 3 print 'Fizz', if its a multiple of 5 print 'Buzz', if
-// it is multiple of 3 and 5 print 'FizzBuzz', for everthing else print the number itself.
-//PS: you can use arithmetic operator modulo (%) - it is remainder when dividing.
-//10 % 3 = 1 - so in 10 we have 3*3 + 1
-//16 % 4 = 0 - as in 16 we have 4*4
-//19 % 4 = 3 - as in 19 we have 4*4 + 3 etc
+// TODO: Time has come for a classic exercise — 'FizzBuzz'.
+
+// Count from 1 to 50 and print numbers out:
+//
+// * If a number is a multiple of three, print 'Fizz'
+// * If it's a multiple of 5, print 'Buzz'
+// * If it is multiple of 3 and 5, print 'FizzBuzz'
+// * For everything else, print the number itself.
+
+// P.S. You may wish to use arithmetic operator remainder (%):
+// It calculates the remainder when dividing.
+//
+// 10 % 3 = 1 — in 10 we have 3*3 + 1
+// 16 % 4 = 0 — in 16 we have 4*4
+// 19 % 4 = 3 — in 19 we have 4*4 + 3 etc
 
 
 
@@ -210,7 +308,7 @@
 
 
 ////////////////////////////////////////////////////////////////////////
-//Congratulations! You have finished Part 2 of JavaScript Basics!     //
+// Congratulations! You have finished Part 2 of JavaScript Basics!    //
 // Stand up, stretch your legs, celebrate your achievement.           //
-//Next step will be following up the instructions in level3.js file.  //
+// Next step will be following up the instructions in level3.js file. //
 ////////////////////////////////////////////////////////////////////////