Introduction to JavaScript
JavaScript is one of the most popular programming languages in the world. I believe it's a great language to be your first programming language ever. We mainly use JavaScript to create
- websites
- web applications
- server-side applications using Node.js
but JavaScript is not limited to these things, and it can also be used to
- create mobile applications using tools like React Native
- create programs for microcontrollers and the internet of things
- create smartwatch applications
It can basically do anything. It's so popular that everything new that shows up is going to have some kind of JavaScript integration at some point.
JavaScript is a programming language that is:
- high level: it provides abstractions that allow you to ignore the details of the machine where it's running on. It manages memory automatically with a garbage collector, so you can focus on the code instead of managing memory like other languages like C would need, and provides many constructs which allow you to deal with highly powerful variables and objects.
- dynamic: opposed to static programming languages, a dynamic language executes at runtime many of the things that a static language does at compile time. This has pros and cons, and it gives us powerful features like dynamic typing, late binding, reflection, functional programming, object runtime alteration, closures and much more. Don't worry if those things are unknown to you - you'll know all of those at the end of the
- dynamically typed: a variable does not enforce a type. You can reassign any type to a variable, for example, assigning an integer to a variable that holds a string.a
- loosely typed: as opposed to strong typing, loosely (or weakly) typed languages do not enforce the type of an object, allowing more flexibility but denying us type safety and type checking (something that TypeScript which builds on top of JavaScript - provides)
- interpreted: it's commonly known as an interpreted language, which means that it does not need a compilation stage before a program can run, as opposed to C, Java or Go for example. In practice, browsers do compile JavaScript before executing it, for performance reasons, but this is transparent to you: there is no additional step involved.
- multi-paradigm: the language does not enforce any particular programming paradigm, unlike Java for example, which forces the use of object-oriented programming, or C that forces imperative programming. You can write JavaScript using an object-oriented paradigm, using prototypes and the new (as of ES6) classes syntax. You can write JavaScript in a functional programming style, with its first-class functions, or even in an imperative style (C-like).
In case you're wondering, JavaScript has nothing to do with Java, it's a poor name choice but we have to live with it.
