why do we use self invoking functions in javascript

1(function(){
2    //Bunch of code...
3})();

1(() => {
2  console.log('Ok');
3})()
4

1(function(){
2  
3	// your code here
4  
5  	/* self invoking functions are used to avoid any name scope collision
6    of variables and functions, specially when you have a huge code in your 
7    file and you also need to add a third party library. Because there is 
8    a high chance of repeating names of variables and functions.
9    
10    Using these functions help solve this problem and names can be used 
11    again and again. Also, this way there is very little clutter in the code
12    and its easily understandable.
13    
14    you alos do not need to call this function in order to make your code work,
15    it runs automatically.
16 
17 	*/
18  
19})();