iife

(() => {
  // statements
})();

result = (function(a, b){
    return a - b;
})(100, 42);

console.log(result); // 58

(function () {
    var aName = "Barry";
})();
// Variable aName is not accessible from the outside scope
aName // throws "Uncaught ReferenceError: aName is not defined"

/*An IIFE (Immediately Invoked Function Expression) is a JavaScript 
function that runs as soon as it is defined
*/

(function () {
        //write your js code here
});