A Handy Tutorial On Utilizing Single Var Pattern In Javascript

As a JavaScript programming professional, I’m sure you too would have been entirely impressed with the flexibility of creating any type of variable. However, if you are still uncertain about working with JavaScript variables, then the single var pattern is a must-know.

What all is covered in this tutorial?

Continue reading this tutorial which makes you familiar with varied benefits attached to utilizing the single var pattern in JavaScript. Plus, you’ll also get to know how to proceed ahead with the same.

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A walk through some remarkable benefits of using the single var pattern in Javascript

1. Utmost code readability

Quite similar to the abstract of a scientific paper, the single var Javascript patten will provide the reader a quick overview of what all the function will do without the need for going through the entire thing from scratch.

2. A reduced possibility of logical errors

With single var pattern, since all variables are declared right at the start of the function block; any issues related to variable hoisting, accidental declaration of global variables and errors related to naming collisions are avoided as a whole.

3. Ease of creating and managing variables

When all the variable are available at one location(as is the case with single var pattern in JS), it becomes quite convenient to create new variables and manage the existing ones. In order to tweak a variable, all you need to do is simply scroll up to the top of the function and start off with altering its variables.

And now, let’s have a look at effective utilization of Single Var Pattern in JavaScript

Single Var Pattern

Well, in the single var pattern, all local variables are being created with the help of a single var statement which is placed at the start of the function block. Each variable included within the function is being separated by a comma(,) with the last variable ending with a semi-colon(;) marking the termination of single var statement.

Here’s an example of the Single Var Pattern:

function customfunction() {

var a = 1,

b = “Welcome”,

c = { name: “Smith”, age: 45 },

d = new Date(),

e;

}

Since spaces, tabs, newlines and other spacing characters both, before and after commas and semicolons are simply ignored in JavaScript, we can replace the above pattern with this:

function customfunction() {

var a = 1, b = "Welcome", c = { name: "Smith", age: 45 }, d = new Date(), e;

}

The above single var pattern is similar to the one shown below, where multiple var statements are being defined for each variable:

function customfunction() {

var a = 1;

var b = "Welcome";

var c = { name: "Smith", age: 45 };

var d = new Date();

var e;

}

Explicit declaration of data type for each variable isn’t necessary in JavaScript’s Single Var Pattern

Since JavaScript is a dynamically typed programming language, you aren’t required to declare the data type for each variable. Rather, you can have a mixture of data types including function literals, strings, undefined, arrays etc.- all in a single var statement, without facing any kind of complications.

Understanding the use of single var pattern using an example

Let’s say we have created a function which returns a randomly chosen integer number that lies between two numerical arguments fed to the function. The code for the same is displayed below:

// This is the function that returns a random integer number

// between two integer arguments already specified.

var randomizer = function (x, y) {

var min = x,

max = y,

random = Math.random(),

result;

 

// Here, the calculation of random integer number is done

result = Math.floor(random * (max - min) + min);

 

return result;

}

// The random integer number will be displayed in an alert box

alert(randomizer(1, 100));

So, you can modify the above code by including the calculation of result variable’s value in a single var statement as shown below:

// This is the function that returns a random integer number

// between two integer arguments already specified.

var randomizer = function (x, y) {

var min = x,

max = y,

random = Math.random(),

// Random number is calculated here

result = Math.floor(random * (max - min) + min);

 

return result;

}

// The random integer number will be displayed in an alert box

alert(randomizer(1, 100));

If you observe the above code carefully, you’ll find a visible reduction in its length. Moreover, since there’s no need for declaring undefined/empty variables, we can easily avoid any kind of redundancy.

An alternative to traditional formatting style for a single var pattern in Javascript

With reference to the example explained above, you can follow the below formatting style for using the single var pattern:

function customfunction() {

var   a = 1

     , b = “Welcome”

     , c = { name: “Smith”, age: 45 }

     , d = new Date()

     , e;

}

In the above style, I’ve placed comma-separators at the start of each line of code. The basic purpose of doing so is to separate the variables so as to make it easy for you to add a new variable into the single var statement.

With that, we’re done!

 

Conclusion

Single Var pattern has been appreciated by global web programmers. If you too intend to take a drive through it, then I’m sure abiding by the above tutorial would help you out.

Author Bio :

Isabella Morris is currently employed with a renowned Magento development company and is also engaged in writing informative articles on best tools and tricks for Magento development. Her write-ups have proved beneficial for a wider group of Magento developers across the globe.

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