Bootstrap Function Declaration [duplicate]

Question

This question already has answers here:

JavaScript plus sign in front of function expression (4 answers)

Closed 8 years ago.

I was taking a look through the bootstrap JS source and I came across something that I haven't seen before:

+function ($) { "use strict";
//...
}(window.jQuery);

What's the deal with the + in front of the function declaration? Is it to mitigate some potential minification problems or something?

I believe that placing a + before an expression type converts the result of the expression to a number, but I don't see what the relevance of that would be here.

Thanks for anybody who can shed some light on this for me.

Answer 1

That is so that the function declaration is a function expression, so that it can be executed immediately.

Usually that is done by putting parentheses around it:

(function ($) { "use strict";
//...
}(window.jQuery));

or:

(function ($) { "use strict";
//...
})(window.jQuery);