What is IIFE in Javascript ? (important interview question)

An IIFE, or Immediately Invoked Function Expression, is a JavaScript function that executes immediately after it is defined. It provides a way to create self-contained blocks of code that don't interfere with the global scope. By invoking the function immediately, it allows for encapsulation and private variable scope.

(function() {
    //write any code , it will automatically run 
  console.log("Hello world");
})();

in this example, an anonymous function is defined and invoked immediately by wrapping it in parentheses. It executes instantly without requiring explicit invocation elsewhere in the code.

(function(name) {
  console.log("Hello, " + name + "!");
})("Diwakar");

in this example, the IIFE takes a "name" argument and logs a personalized greeting. the argument "Diwakar" is passed when invoking the IIFE.

use case:-

1- Avoiding global namespace pollution

2- compatibility with older javascript

3- Encapsulating code

4- Modular Pattern

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