JavaScript: Loops

For loop: For variable i, if i is less than 5, then add 1. i = i + 1 will be solved on the right, then assigned to the left. So i + 1 is done, then if i is 1, 2 will be assigned on the left as the new value of i. Console.log simply writes the result, which would be 1, 2, 3, 4, and 5.

var i;
for (i = 0; i < 5; i = i + 1)
{
    console.log(i);
}

For loop using "++" . The only difference here is the shortcut ++ which is equivalent to i + 1.

for (var i = 0; i < 3; i++)
{
    console.log(i);
}

For-in loop: will iterates over enumerable properties of an object. Enumerable properties are non-shadowed, user-defined property (including inherited properties)-- not built-in properties, for ex. toString. They follow this formula: for (variablename in object){statement or block to execute}. This is a great resource for more on these specifically, their exceptions, and other nitty gritties.

var aProperty;
document.write("Something's Object Properties
 ");
for (xProperty in Something)
{
  document.write(xProperty);
}
document.write("Exiting loop.");

While Loop: If i is 99, and if that value of i (99 currently) is greater than 0, run this code. This code says to print "99 red balloons," then subtract 1 from i.. so now i is 98. And loop back to the top. So, now i is still greater than 0, write "98 red balloons," subtract one.. and so on..

var i = 99;
while (i > 0)
{
    text += (i + " red balloons");
    i -= 1;
}

Do while loop: This is essentially the same and a variant of the while loop. If i is 0, then print out "I know how to count! 1" and add 1 to i, so i will be 1 now.. and the following will now be printed "I know how to count! 2," and so on.. until i hits 10. So, the last number actually printed will be 9, because after 9 is printed, you will add one and the code will exit because i is no longer less than 10.

do {
    var i = 0;
    text +=  "I know how to count! " + i;
    i++;
   }
while (i < 10);

NOTE: The difference between the while loop and the do while loop is that in the do while loop, then the code block is executed AT LEAST ONCE before the condition is tested no matter if it is true or false (because the while is at the end after execution). The while loop will only execute for the scenario if it is true.

Read More

Introduction to JavaScript pt. I

"A method method is used to define new methods."

Function.prototype.method = function (name, func) {
 This.prototype[name] = func;
 Return this;
    };

// exclusively for commenting You can get syntax errors using /* */

Names can be anything that is a letter followed by more letters, #'s, or underbars-- EXCEPT for the following reserved words which will tell the program to do a certain task (these should be familiar if you have done any other programming) such as abstract, long, return, etc…

Numbers in JS have only one type and is 64 (wholeee) bits as a floating type. To explain how it is all one type.. in JS, 10 and 10.0 are equivalent. This eliminates the need to know what type of number to call when you are programming. You can use exponents by placing an e, so 1e2 would represent 100.

NaN is not equal to any value, even itself (to me this is an entertaining idea). JS ises the function below to determine if something has a value or not: isNaN(number)

If you use infinity as a value it will go to about 1.8e+308 -- I think that's quite infinite. That’s a lot of moles of Avogadro's numbers of molecules etc..

I had a chemistry professor one day who said if we brought him Avogadro's constant in pennies he would give us an A. Avogadro's number in chemistry is: 6.0221413e+23 :D think about that for a second!

The following method will convert any number --> integer:

Math.floor(number) 

Strings have characters inside them and backslash is an escape character. There is no character function, so just put one character into a string-- same ideas as the number system mentioned above. Strings have a length property that counts the number of characters in it. For example, "one".length would give you 3, because there are three letters in the word "one."

You can concatenate strings together as the following are equivalent:

'w' + 'o' + 'r' + 'd' === 'word'

There are many types of statements to "do stuff" with JS, and logically, it goes top to bottom.

• conditional statements (if/then and switch)
• looping statements (while, for, and do)
• disruptive statements (break, return, and throw)

Literals can specify new objects and their properties will either be a name or string. Because literals are not considered a variable, the property name has to be known when compiling.

Source: Crockford, Douglas. "JavaScript: The Good Parts." O'Reilly Media / Yahoo Press. (2008).

Read More

JavaScript Escape Characters

In JavaScript, strings are written as characters inside single or double quotes. Hence, you cannot make a string have quotes inside of it or do other functions.. because it is simply a string and won't recognize it as a function. So, if you are doing something inside of quotes, you have to use these backslashes to make escape characters. These characters will "escape" the rules of the string!

For example, JS will see this string:

"Hello my name is "Crystal Tenn.""

.. as "Hello my name is "

You can use escape characters by putting a backslash before the quotes.

"Hello my name is \"Crystal Tenn.\""

And, this will print what we wanted: "Hello my name is "Crystal Tenn.""

Another example in shell I like is the following:
This is a common way to delete all files in the current directory:

rm *    

This is how to delete a particular file called *.

rm \*   

The following is a list of escape characters in JS:

• \' single quote
• \" double quote
• \\ backslash
• \n new line
• \r carriage return
• \t tab
• \b backspace
• \f form feed
• \v vertical tab
• \0 null character

Read More

Most Commonly Used git Commands

Just a reference for some of the most common git commands out there! Explanation of each on top, and below is the command for Git bash.

Setting up with remote GitHub:
See existing remote branches:

$ git remote -v

Adding from Git Repository (URL found on bottom right menu of GitHub), this one is "origin" for me, but you can name it other things if you have a specific name for a certain connection:

$ git remote add origin https://github.com/YOUR-USERNAME-HERE/NAME-OF-PROJECT.git

Removing from local (replace "origin" with whichever branch you want to remove):

$ git remote rm origin

Version Control in a Team Setting:
Committing your work locally and in quotation marks, add a descriptive message of the changes made. Make sure it RUNS before doing this!

$ git commit -am "Adding something cool and describing it very well in this message.."

Push your local changes up to Git for all to see. DOUBLE make sure it RUNS. Master here if you do not have other branches. If you do, then this will change depending on what and how much you wish to push. Origin here is the one I am working with, like I mentioned, this could change depending on what you are working with at the time.

$ git push origin master

Pull down changes from others. Same deal with the master branch and origin as mentioned above.

$ git pull origin master

More to be added soon.. !

Read More

Difference: git pull vs. git fetch

I saw these two buttons the other day in VS (Git hooks up into VS directly!) and was wondering on the exact difference between git pull vs. fetch. And, I figured I would share!

git fetch will update remote-tracking branches under refs/remotes// and commits the target branch to your current branch locally. It will not merge into the current branch until you use merge. It allows you to do the process step by step and it great for keeping up to date on the repository and seeing the difference between conflicts (if there are any).

git pull is what syncs local branch with its remote version on Git. AND it will update other remote-tracking branches. git pull does a git fetch followed by a git merge (and always works onto the currently selected branch). This function will pull commits into EVERYTHING (including what you are currently working in) so it is best to stop and save before and do this only if you do not forsee any conflicts. It will merge the commits without letting you see and decide for yourself. There can be big conflicts using this, however it lets you skip the step to merge.

In my opinion, it is much safer to work with git fetch because it allows you to resolve conflicts on your own and have a hand step by step in controlling the changes to your work. git pull may save a step, but the risk of conflicts causing the code to break is too risky unless it is a very simple code or simply new files added where you know there will not be any conflicts raised.

Read More

MVC Conventions

Conventions are important because of the efficiency and simplicity of finding your own work where it "belongs", and for others' to contribute and collaborate!

They are as simple and important as capitalizing the first word of every sentence or adding commas and periods as needed! Imagine what a pain it would be if books (and blog posts!) were written without common conventional grammar rules. The same goes for general programming. Here are the MVC conventions to keep in mind (usually not REQUIRED, but also usually EASIER to keep to these):

• Controllers folder should contain all of the application’s controller classes.
• Controller classes all end their names with the Controller suffix (ex: MovieController).
• Views contains the files that the user will be able to browse.
• Views can have subfolders: Shared and an optional folder with views for each Controller.
• When a Controller is specifically making data for a certain View and encapsulated in a View Model: name it ActionViewModel (change out Action for what the Action actually is!).
• "RequestModel" for in-bound data & "ResponseModel" for out-bound data.
• HTML Form fields should have the same name as Model Properties.

Additionally, Microsoft .NET recommends the following:

• UpperCamelCase ("Pascal Style") for most identifiers
• lowerCamelCase is for parameters and variables

Read More

Razor for the web (HTML rendering)

Razor is a type of syntax combining content with code. Essentially, its nothing new, and uses the same concepts from .NET code languages and HTML. If you can do those, then it is simple to implement Razor onto your website to make certain features easier to add and use. All razor is processed and removed on the server before the page is posted to the browser for the user. Thus, users do not see it (even the comments and inclusive of the "view source" file).

Today is: @DateTime.Now

And the following will be output onto the page, seemingly looking just like the rest of the HTML plain text on it:

Today is: 7/8/2014 4:56:04 PM

You can see how it combines HTML div tags with some .NET properties (DateTime.Now). Razor uses pieces of both to simplify tasks and shoot an output to the browser for users. The syntax can vary sometimes from both, but tends to be shorter and simpler. Overall, the goal is to render HTML and make life easier for the web developer.

In Razor, the expression begins right after the @ symbol and ends at the closing bracket.

As a sample:
If/else statement using Web Forms syntax:

<% if(User.IsAuthenticated) { %>
    Hello, <%: User.Username %>!
<% } %>
<% else { %>
    Please <%: Html.ActionLink("Login") %>
<% } %>

Razor syntax:

@if(User.IsAuthenticated) {
    Hello, @User.Username!
} else {
    Please @Html.ActionLink("Login")
}

Though they use a different syntax, both render the same HTML to the browser!

Source: WPF 4.5 Unleashed

Read More