What is the purpose of this? (function ($) { //function code here })(jQuery);

Question

I am debugging someone else\'s JavaScript code and a majority of the code is wrapped like this:

(function ($) {
    //majority of code here...
})(jQuery);
         


        

Answer 1

Just to expand on RightSaidFred's answer a little, when I first saw the ()() syntax I was a bit befuddled, but it made sense once I realised the brackets are being used to define an anonymous function and then call it. e.g:

(function (msg){alert(msg)})('hello');

... defines a function and then calls it, passing 'hello' as a parameter.

So the example in the question:

(function ($) {
    //majority of code here...
})(jQuery);

is passing jQuery into an anonymous function and referring to it as $ within the function, a way of guaranteeing that $ will work for jQuery without interfering with anything else.