JavaScript Functions: Function Properties

Since JavaScript functions are objects they can have properties that belongs to the function itself.  For example this simple example counts the number of times the function is being called by incrementing the counter property that belongs to the function.

    <script>
        functionCount.counter = 0;

        function functionCount() {
            return functionCount.counter++;
        }

        for (var i = 0; i < 10; i++)
            functionCount();

        console.log(functionCount.counter);

    </script>

JavaScript Array Deep Dive: Adding and Deleting Elements Array.push(), Array.unshift(), and delete

When you define an object as an Array in JavaScript you get the benefits of inheriting some useful methods with it.  Some of the common methods are those that allows you to add and delete elements from an array.  The .push() method adds an element at the end of the array, the unshift() method adds an element at the beginning of the array.  The delete keyword deletes an element at the specified index.

Let say you have an the following array:

var numbers = [3,4];

If you output the array in the browser console you will see that the array has two elements with the number 3 occupying index 0 and the number 4 occupying index 1.

JavaScript : The switch Statement

The switch statement is there to make the code more readable if the if statements contains too many branches and becomes too hard to read.

Consider the code below

var x = 6;

if (x === 1)
{
     console.log("one");
}
else if (x === 2)
{
     console.log("two");
}
else if (x === 3)
{
     console.log("three");
}
else if (x === 4)
{
     console.log("four");
}
else if (x === 5)
{
     console.log("five");
}
else
{
     console.log("x is not 1-5");
}

JavaScript Array Deep Dive : Iterating Through Array

Since an array is a collection of elements of objects, values, etc.  The most common function performed on it is to iterate through each elements of the array.  The most frequent way to do that is with a for loop.

Let's say you have an array with the following:

var numbers = ["one","two","three","four","five"];

The numbers array above contains five string elements, which also has a indexes associated with the it.  There's also a length that is defined with each array that we will use for the for loop we are about to write.  So what do the you length of the numbers array will be?

If we output the array to the browser with the statement console.log(numbers.length) do you think we will get the length to be 5 or 4?

If you guess 5 you are correct because there are five elements in the array.  However, the arrays have zero based indexes therefore the index is always length -1

for(var i = 0; i < numbers.length; i++)
{
     console.log(numbers[i]);
}

JavaScript : Multidimensional Arrays or Arrays of Arrays

JavaScript itself does not have multidimensional arrays, instead you can use an arrays of arrays instead.  Multidimensional arrays are basically arrays that you can reference by rows and columns.  The most obvious real world use is to store rows and columns of a database record.  Imagine if you have a row of the database product from the database from the table "Products".  Instead of storing each value in an individual variable you can store them in an arrays of arrays.

Let's say you have the following database Products table

MongoDB In-Depth: Installing MongoDB on Windows

In the previous post we installed MongoDB on Linux on this post we are going to install MongoDB on Windows.

Here are the steps:

1. Go to https://www.mongodb.com/download-center/community, then click on the "Download" button

JavaScript Array Methods: The Array.reverse() Method

The Array.reverse() method reverses the order of the array elements.  The easiest way to demonstrate this is to have an array with the numbers 1 to 5.  If we call the Array.reverse() method we should get an array of 5 to 1.  The Array.reverse() does not create a new array, it simply rearranges the array into a new order.  Just keep that in mind when you are using this method.

So let's declare our array from 1 to 5

    <script>
        var numbers = [1, 2, 3, 4, 5];
    </script>

So if we call the numbers.reverse() method we should get an array of 5 to one in the reverse order

JavaScript Basics: The for loop

The for loop is a looping construct in JavaScript that are more simplistic than the while loop.   When writing the for loop there are three three parts they are

1.  Initialize - a count variable is initialize, it's usually zero but it doesn't have to be
2. Test - A test to see if the loop should continue
3. Increment - finally the count is incremented, it doesn't have to be an increment it could be decrements as well

JavaScript Array Methods: forEach()

The forEach() method loops through an array, and performs a function on each element of the array.  The forEach() method can take three arguments, the first argument is a current value that you want to perform an action on.  The second argument acts as the "this" value within the scope of the function.  The third argument is the array itself.  Most of the time only the first argument is passed.  The code below passes in only one argument which is an anonymous function being performed on each element of the array using the forEach() method to calculate the oil prices in the last five days and prints it out in the console.

    <script>
        var oilPrices = [70.15, 69.50, 71.23, 74.32, 76.99];
        var total = 0;

        oilPrices.forEach(function (value) { total += value });

        console.log(total);
    </script>

Iaas With AWS: Setup SSL/TLS With Application Load Balancer Part 4

 In the previous post we created a load balancers with the target groups, rules, and instances to handle HTTPS traffic.  In this post we are going to set up our DNS records in Route 53. So go to the Route 53 dashboard, click on your domain

1. Click on "Create record"