Is an IIFE immediate?

An IIFE, or Immediately Invoked Function Expression, is a JavaScript function that is defined and executed right away. It is written as a function expression wrapped in parentheses, followed by another set of parentheses to invoke it: (function(){ / code / })(); The outer parentheses force the function to be treated as an expression, not a declaration, allowing the trailing parentheses to call it immediately. IIFEs are used to create a new lexical scope, preventing variables from leaking into the global namespace. They are also handy for initializing modules, setting up private state, or executing code that should run once during script load. Because the function runs immediately, any variables declared inside are not accessible outside, which helps avoid naming collisions and keeps the global scope clean.