An Immediately Invoked Function Expression (IIFE) is a JavaScript function that runs as soon as it is defined. It is commonly used to avoid polluting the global scope or to create a private scope for variables.
Here’s a simple example of an IIFE:
(function() { var message = "Hello from IIFE!"; console.log(message); })();
Hello from IIFE!
IIFEs are useful when you want to create a new scope, especially to protect variables from being accessed or modified outside of the function:
(function() { var counter = 0; // This counter is private and can't be accessed from outside function increment() { counter++; console.log(counter); } increment(); // Logs: 1 increment(); // Logs: 2 })(); console.log(typeof counter); // Logs: "undefined", because `counter` is not accessible here.
This ensures that variables like counter remain private and are not accidentally modified or accessed from other parts of the code.
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