ECMAScript 6 (or ECMAScript 2015) has remarkably improved parameter handling in JavaScript. We can now use rest parameters, default values and destructuring, among other new features. In this tutorial, we will explore arguments and parameters in detail and see how ECMAScript 6 has upgraded them.

Having a good understanding of constructors is crucial to truly understand the JavaScript language. Technically, JavaScript doesn't have classes, but it has constructors and prototypes to bring similar functionality to JavaScript. In fact, the class declaration introduced in ES2015 simply works as syntactic sugar over the existing prototype-based inheritance and does not really add any extra functionality to the language.

In JavaScript, there are several ways to count the occurrences of some text or character in a string. If you need to find the occurrences of a single character, then using the charAt() method inside a loop is the easiest method. Let's look at some examples.