What is IIFE (Immediately Invoked Function Expression)?

IIFE — is a function that is declared and immediately executed.

(function() {
  // Function code
})();

• Declaration and invocation: Immediately after the declaration (inside parentheses), there is an operator (), which calls this function.
• Creating a private scope: Variables and functions declared inside the IIFE do not pollute the global scope.
• Code isolation: Allows avoiding name conflicts when using multiple JavaScript libraries or scripts.
• Solving closure issues in loops: Helps "capture" the correct value of a variable in each iteration.

// Example of using to create a private scope
(function() {
  var privateVar = "PrivateD";
  console.log(privateVar); // Will output "Private"
})();

// console.log(privateVar); // Error: privateVar is not defined