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Practice

Advanced Features of Functions

Let's explore more advanced ways to use functions.


Callback Function​

A callback function is a function that is passed as an argument to another function.

Calling a callback function passed as an argument
function study(callback) {
  console.log('Studying...');
  callback(); // Call the callback function
}

study(() => {
  console.log('Finished studying!');
});

Recursive Function​

A recursive function is a function that calls itself.

Implementing factorial with a recursive function
function factorial(n) {
  if (n === 1) return 1;
  return n * factorial(n - 1);
}

console.log(factorial(5)); // Outputs 120

IIFE (Immediately Invoked Function Expression)​

IIFE is a pattern where a function is defined and immediately invoked.

Example:

Using IIFE
(function () {
  console.log('This function runs immediately!');
})();

Built-in Functions and Usage Examples​

JavaScript provides many useful built-in functions. For example, it supports functions to sort arrays or slice strings.

Example:

Using the built-in sort function
let arr = [3, 1, 4, 1, 5, 9];
arr.sort();
console.log(arr); // Outputs [1, 1, 3, 4, 5, 9]

let str = 'Hello, world!';
let slicedStr = str.slice(0, 5);
console.log(slicedStr); // Outputs "Hello"

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