JavaScript Objects Functions and Arrays Explained

How many times have you attempted to learn JavaScript, only to put it on the side because it was too complex or you felt overwhelmed by the information overload?

JavaScript Objects Functions and Arrays Explained is easy to understand with plenty of illustrations and links to code files you can physically copy. Easy does not mean simple, it will not insult your intelligence and capacity to learn new concepts. This is a serious book for those wanting to understand how JavaScript works.

This book can be used as a reference if you need a detailed explanation on how a certain method works.
The key to master JavaScript is to become familiar with its library methods.

Get it today and start learning. You don’t need to own a Kindle. You’ll be able to read it on anyone of your computers by downloading the free Kindle app.
–> JavaScript Objects Functions and Arrays Explained

book_object

Fahrenheit to Celsius – JavaScript and AngularJS

You probably know how to convert Fahrenheit to Celsius in JavaScript but how would you display it on a web page?

Google has come up with a modern solution: AngularJS

AngularJS is a way to make your HTML more dynamic and it is easy to implement.

Take a look at my sample here:
http://jsplain.com/javascript/index.php/Thread/45-Fahrenheit-to-Celsius-ng-model/

Have fun testing it!
Tony

Finding the smallest factor of a number with JavaScript

Time to practice some code!

Create a function named smallestFactor that finds and displays the smallest factor of any number (num).

Then call the function by passing in the value of  100. It should display the number 2 as a result.

Whenever you’re ready to look at my examples please refer to
http://bit.ly/1sDxC2O

Tony

A counter for a for loop in JavaScript is not essential

Did you know that a conditional expression controlling a FOR LOOP does not have to be a counter?
That’s right, all it needs to be is a Boolean expression of any kind.
Take the following loop as an example:

var finish = true;

for (var i = 0; finish === true; i++) {

    if (i >= 5) {
        finish = false;
    }

    console.log(i);
}

// result: 0,1,2,3,4,5

Variable finish is originally true and as long as it is true the for loop will run just like a while loop would.
Then we can control the loop at any time by switching the value of finish to false as it was done by the conditional statement.

READ MORE HERE: http://bit.ly/1BWiSEI

Dot Syntax

What is the meaning of the dot?
The dot signifies that we want to use something that’s inside something else.

console.log("log is inside of a console");

myObject.search("Tony de Araujo");
// search is a method which is inside of object myObject

Hope it helps!

Can we run JavaScript tests on the Windows command prompt?

Yes we can ( once we install Node.js on our machine).
Node.js was first published by Ryan Dahl in 2009 and could only run on Linux.In June 2011, Microsoft partnered with Joyent to help create a native Windows version of Node.js.
Node.js is a cross-platform runtime environment for server-side and networking applications. Once installed on Windows we can do lots of things with it, one of such benefits is to run JavaScript on the command prompt.

Installation only takes minutes. Please see my other article on how to go about it, from installation to testing JavaScript on the command line:
jsplain.com/javascript/index.php/Thread/26-Running-JavaScript-tests-on-Windows-command-prompt/

Happy first of September, everyone!

forEach, a way to manipulate arrays

The array method forEach( ) was introduced with ECMAScript 5 when nine new methods were added to help developers create ways of searching and manipulating array contents. These methods perform operations that previously would require complex iterative loops. The nine additional methods are: indexOf, lastIndexOf, every, some, forEach, map, filter, reduce, reduceRight. All these methods are variations of the forEach() method which I’m about to discuss.

forEach( ) performs a specified action for each element on the array. The specification of what to do is written by the programmer as a function in the form of an argument to the forEach() mechanism.

Remember, the purpose of a function is to store some code that will run when the function is called. We create the function, and forEach() will process it.

So, forEach( ) takes a function as its argument. The parameters of the function itself will interface with each valid element of the array in an iterative manner, just like a loop would do. By valid element I mean an element with data ( not an empty element location). Array indexes not having a value, or the value being undefined (if any), are ignored.
1- Let’s experiment with this method in increments. Start by introducing on the console a new array (I’m using Chrome):

var g = ["red", "blue", "white"];

2- Call forEach( ) on the array g by using a function with just one parameter, “y” , and in the function we stored a simple console.log output:

g.forEach(function(y) {
console.log(y);
});

The function being used here may contain up to 3 arguments. The first argument (as the example above), points to the array data. In the forEach( ) example given above, the parameter y will point to the value of each index on the array, and the method forEach will process each value according to the instructions on the body. In this case the next instructions are to console.log each value at each “y” iteration and the result is: red blue white (in separate lines).

For a more detailed explanation as well as an explanation of all the other 8 methods please refer to my eBook: