Solved

When to use a function or a var

Posted on 2015-02-05
6
67 Views
Last Modified: 2015-02-10
Hi,

In JavaScript when would you use a var over a function or vice versa?
Or is it just personal preference?

I.e

var investment = function(){};
as opposed to
function investment() {};
0
Comment
Question by:Soluga
6 Comments
 
LVL 11

Expert Comment

by:Dany Balian
ID: 40590685
Well it has to do with reusability! If u want to use the function al over again then use functions! If it's a one time thing then just type it!
0
 
LVL 1

Author Comment

by:Soluga
ID: 40590868
Hi Danny,

So would you then use a var to create an instance of the function?
Such as ..

var = investment();

function investement(){};
0
 
LVL 32

Assisted Solution

by:Big Monty
Big Monty earned 250 total points
ID: 40591414
if you expect a value to be returned from the function, then it would be better to put it a variable. if not, then just calling the function by name would be the best way to go (purely for readability purposes)
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 11

Accepted Solution

by:
Dany Balian earned 250 total points
ID: 40593032
if you need to use the var many times.. then yes you do that..
instead of doing

if (getproductdiscount()>0) {
total = total + getproductdiscount();
} else {
total = total - getproductdiscount();
}
in this case getproductdiscount() will be executed and calculated 3 times

however
var disc=getproductdiscount();
if (disc>0) {
total = total + disc;
} else {
total = total - disc;
}
will run the function just once
0
 
LVL 11

Expert Comment

by:louisfr
ID: 40593043
I think this explains the difference between function declarations and function expressions : https://javascriptweblog.wordpress.com/2010/07/06/function-declarations-vs-function-expressions/
0
 
LVL 11

Expert Comment

by:louisfr
ID: 40600192
It's interesting that you accepted those two comments even though they answer a completely different question.
What they answer is why put the result of a function call in a variable
result = myfunction();
if (result > 0)
    total = total + result;

Open in new window

vs. using directly the result of the function.
if (myfunction() > 0)
    total = total + myfunction();

Open in new window

Your question was about the difference between a function declaration
function investment() {}

Open in new window

and a function expression
var investment = function(){};

Open in new window

0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

jQuery is a JavaScript library that greatly simplifies JavaScript programming. AJAX is an acronym formed from "Asynchronous JavaScript and XML."  AJAX refers to any communication between client and server, when the human client does not observe a…
International Data Corporation (IDC) prognosticates that before the current the year gets over disbursing on IT framework products to be sent in cloud environs will be $37.1B.
The viewer will learn the basics of jQuery, including how to invoke it on a web page. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery.: (CODE)
The viewer will learn the basics of jQuery including how to code hide show and toggles. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery…

895 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now