what's wrong with my Self-Executing Anonymous Function in javascript

Question

I try to write a javascript Self-Executing Anonymous Function

window.App = window.App || {}

    (function (global) {
        global.test = function () {
            console.log('test');
        }
    })(App);

$(function () {
    App.test();
})

but the fire bug tell me: ({}) is not a function

then I try move the (app) in, like:

(function (global) {
    global.test = function () {
        console.log('test');
    }
}(App));

then the firebug tell me :

App is not defined

So wht's wrong with my code?How can I do it in right way?

here is the demo

This code looks a little strange to me so I won't provide an answer, but shouldn't there be some code between the curly braces on the first line? — Jezen Thomas, Jun 25 '12 at 08:08
@JezenThomas no, the {} is just a way of creating an empty object. You can see it gets passed into the function as *global*, where it gets a method *test* defined on it. — McGarnagle, Jun 25 '12 at 08:13
That is a nice example for problems with semicolon insertion in the wild. Kids, never forget your semicolons! — kioopi, Jun 25 '12 at 08:14
Very interesting. Great question; not sure why it's been downvoted. +1 — Jezen Thomas, Jun 25 '12 at 08:24

score 7 · Accepted Answer · answered Jun 25 '12 at 08:05

7

Try this:

window.App = window.App || {};

You are missing a semicolon there!

answered Jun 25 '12 at 08:05

Amberlamps

39,180
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JavaScript does automatic semicolon insertion at the end of every line, if this does not result in a syntax error. The two lines should be equivalent. – cdhowie Jun 25 '12 at 08:06
@cdhowie Not always, and this is a perfect case and point. – Trevor Jun 25 '12 at 08:06
@cdhowie no, a semicolon is required here since the next token is a `(`. – Esailija Jun 25 '12 at 08:07
And there you have it, a [semicolon saves the day](http://jsfiddle.net/bradchristie/jczcx/). – Brad Christie Jun 25 '12 at 08:08
Ridiculous! I think the OP deliberately constructed this question to prove a point. – funkybro Jun 25 '12 at 08:10

score 1 · Answer 2 · answered Jun 25 '12 at 08:10

1

Add a semicolon to your first row

window.App = window.App || {};

JS thought that that the parentheses on row 3 was part of your new empty object on row 1.

answered Jun 25 '12 at 08:10

Attila Szeremi

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what's wrong with my Self-Executing Anonymous Function in javascript

2 Answers2