JavaScript has always been an interesting language. Its unique position as the programming language of the web has something to do with its popularity, but I think its creators also deserve credit for language design decisions made in designing the language.

In practicality, JavaScript is at the forefront of multi-paradigm programming. For many developers I bet JavaScript was the first language they used functional programming in. In the classical, recognizable sense this is true with features like Array.prototype.map, Array.prototype.reduce, and the like, but it's commonly used at the basic level of a function being passed around as a first-class object. Without really being clued in to what functional programming is, people will learn some of the event processing facilities useful for web development. the window "load" event and button "click" event are common examples of events beginners learn about early on.

JavaScript is also a lot of people's introduction to reflective programming, which is really so accessible in JavaScript that a lot of people don't really think of it too much when doing it, at least at first.

Perhaps the most interesting feature of JavaScript is the prototype-based object model JavaScript uses. It's the only popular modern language to go this route, but it works for it. Especially considering how ubiquitous class-based object-oriented became on server-side langauges during JavaScript's lifetime this is impressive. Prototype-based object-oriented puts a lot more emphasis on objects than class-based, which to me makes it perhaps the model that deserves the name object-oriented more. The ability to create one-off objects with the option to add any and all desired properties at any time has been used extensively on the web by many JavaScript libraries.

There are downsides to JavaScript's object model being different to the main competing concept. Most notably that users coming from class-based languages often have trouble figuring out how JavaScript objects and constructors work. JavaScript classes are I guess a response to this, and also provide a way to make things such as HTMLElement extensible, as they aren't really JS objects. Additionally, probably because of the bracket notation for accessing properties, people will create an object where semantically they are really trying to use an associative container such as JavaScript's Map, and I've had trouble explaining to even some relatively senior developers that the JavaScript object doesn't necessarily have the same performance expenctations as a proper Map.

Given the above it might be fair to say there are a lot of developers who work with JavaScript but don't fully understand JavaScript. Developers from all backgrounds too, as colleges with computer science programs seem to invariably begin with class-based object-oriented languages and don't really go into how JavaScript is different in say, a programming languages course. If even these people that we consider trained, professional developers don't get it, are we at risk for losing the sense of what defines JavaScript?