Javascript function definition error

Question

var add = function addnums(a,b)
{
    return a+b;
}
alert("sum is " + addnums(10,20));

why can't i use addnums directly in the above Javascript ?

PS : I know other alternatives, the question is why the above specified method doesn't work.

Good question :) I expected that it would just work the way you did it. So that you can either call the function via `addnums(1,2)` and via `add(1,2)`. — sdepold, May 20 '13 at 07:27
addnums() wont be visible in outer scope, its a Named Function Expression — Sudhir Bastakoti, May 20 '13 at 07:27

score 0 · Answer 1 · answered May 20 '13 at 07:26

0

You can.

var add = function addnums(a,b)
{
    return a+b;
}
alert("sum is " + (function(a,b) { return a+b; })(10,20) );

Plus you may shorten the syntax:

var addnums = function(a,b) { ... }

or

function addnums(a,b) { ... }

answered May 20 '13 at 07:26

Jan Turoň

31,451
23
125
169

1

Since all answers receive quick downvotes here, please explain why. – Jan Turoň May 20 '13 at 07:28
i am aware of other methods to make that work, just wanted to know why the method in question doesn't work – nik7 May 20 '13 at 07:28
1

You're not answering the question. The question is about why the function can't be referred to as `addnums` after it's been declared. – JJJ May 20 '13 at 07:29
I see. Recently I've found some article about it, please wait for edit... – Jan Turoň May 20 '13 at 07:31

score -1 · Answer 2 · answered May 20 '13 at 07:31

-1

You have an error writing the function write like the following:

var addnums = function(a,b)
{
    return a+b;
}
alert("sum is " + addnums(10,20));

:)

var add; is a declaration. Here add is declared and assigned a function you need not name the function after keyword function, variable name will take the function name when you define a function in this way. I think you understand now.

answered May 20 '13 at 07:31

Md Toufiqul Islam

178
6

3

Besides the fact, that the syntax of the questioners code is correct, he wants to know why the named function isn't callable via its name. – sdepold May 20 '13 at 07:32
function expression does not need a name, even if you name it it will not be called by that name. This is anonymous. You can say it is a drawback but there are more advantages than disadvantages. Check out this link http://javascriptweblog.wordpress.com/2010/07/06/function-declarations-vs-function-expressions/ – Md Toufiqul Islam May 20 '13 at 10:42

Javascript function definition error

2 Answers2