IIFE Immediately Invoked Function Expressions Javascript

• WhSelf Reviewed. is IIFE?
  • IIFE means Immediately Invoked Function Expressions.

(function square(num) {
	console.log(num * num);
})(5); // can also pass arguments

Q. What will be the output of the following code?

(function (x) {
	return (function (y) {
		console.log(x); // 1
	})(2);
})(1);

• You may think the answer is undefined but the answer is 1
• This is because of Closures Javascript
• The ability of a function, to access variables & functions that are lexically out of its scope are called closures.