How to use (function (global) {...}) (this);

Question

In this thread, I found a piece of JavaScript code that I want to use.

The code looks like this:

(function(global) { // the function code comes here })(this); 

How can I call this function to execute the code? What do I need to pass for this global variable?

Answer 1

The function is immediately executed; you are not executing it by calling it.

This is the definition of a function literal, followed by two parens parameters, which calls this function to be called immediately. Read more: Expression of Expressed Function (IIFE)

No matter what code you put inside, it runs immediately. Everything that is placed in paired calls is passed to the function as an argument. Assuming your code sample has been defined in the global scope, this is a window object and calls it global in the function body. This is a great way to encapsulate your programs to avoid variable conflicts, forced mode, and more.

Answer 2

This design defines the function:

 function(global) { // the function code comes here } 

and immediately calls it, passing this as a parameter:

 ([function])(this) 

The global identifier is simply the name of this parameter inside the function body. For example, try

 console.log(this); // outputs something (function(global) { console.log(global); // outputs the same thing as above })(this); 

Answer 3

How can I call this function to execute the code?

It is already called: (this)

What do I need to pass for this global variable?

this