未捕获的TypeError：对象不是“（（function（$））”上的函数

Question

Why do I get the following error...

Uncaught TypeError: object is not a function

...at the following line, of a certain JS script?

(function($){

And why do I get that error only when JS are concatenated? (I'm using Gulp)

And why does it work if I add ; before that line, like that:

;(function($){

?

update

The preceding line - that is, the object which is not a function, according to the runtime error - on the concatened script was a } , as in:

storage = {
   //...
}

I'm used to always put semicolon, but not after curly braces.

Turns out the curly braces could delimit the end of a statement, like in this case, and then it's recommended to use the semicolon to avoid this error. Here 'sa good explanation.

Answer 1

Javascript ignore missing semi-colon and try to interpret it. So if you don't input the semi-colon, it use the next line to see if it should end the line or chain it.

That allow you to use thing like this :

String
.split();

and it will be interpreted like that :

String.split();

But , this would also work :

String
.split
();

Now, If you have something like this :

var a = 'a';
var b = a
(function(){})

JavaScript has no way to know what you really want to do, so it will interpret it like that :

var a = 'a';
var b = a(function(){});

Giving you the error [place object type here] is not a function

Bottom line, always put your semi-colon.

---

Edit

After seeing your code, here how it is interpreted :

storage = {/**/}(function($){})(jQuery);

So Object ( {} === Object ) is not a function

Answer 2

When concatenated it believes you're trying to call whatever precedes the (function($) {...} .

If you put () after a reference it tries to call whatever the reference is. This is why you'll see a lot of JavaScript libraries precede their code with a lone ;