! function in javascript?

Question

I apologize for my stupid question, I am not good at javascript and angularjs. I've been referencing the code of some projects, and I'm really confused about this, what it actually is !function(a,b,c){}(x,y,z). I have never seen it before. I am not good at javascript nor angularjs. Thanks for all the help!

!function (e, n, t) {
    "use strict";
    // code
}(window, angular, jQuery)

Answer 1

it just simply tell the js to ignore this function and

it make it undefined Like This:

    function Demo(){
    console.log('log something');} 

OutPut Will Be :

log something

But If You Put A ! Before The Function The Result Would Be:

Demo is not defined