If you write JavaScript, you have probably used higher-order functions and not even noticed. If you have ever replaced a for loop with an array method, you’ve used higher-order functions.

JavaScript is also the most popular coding language. According to the 2018 Stack Overflow Developer Survey, JavaScript has been the most used programming language by developers for six years in a row.

Based on open standards, AJAX uses a browser built-in XMLHttpRequest object, JavaScript and HTML Document Object Model (DOM) to exchange data between a web browser and web server, and to display this ...