JavaScript essentials

JavaScript is a popular, single-threaded, synchronous programming language that helps us mostly to build interactive web applications. Its strength is its ability to mix different programming methods. This mix lets you write code in several ways: focusing on objects, using functions like building blocks, reacting to events, or giving step-by-step instructions, making your code clear and easier to handle. The JavaScript you use in the browser or in Node.js is not completely native. That is why we need to differentiate between the concepts of the JavaScript engine and the JavaScript runtime.

JavaScript engine

A JavaScript engine is a special type of program that reads, parses, and translates our JavaScript code into computer-understandable language (machine instructions) – see Figure 3.1. We don’t have one single JavaScript engine for all browsers. For instance, Google Chrome, Opera, and the latest Microsoft Edge browsers use the V8 engine, Firefox...