JavaScript is a lightweight, interpreted, or just-in-time compiled programming language with first-class functions. It is most well-known as the scripting language for web pages, but it can also be used in other environments, such as Node.js, Apache CouchDB, and Adobe Acrobat¹.

JavaScript is a prototype-based, multi-paradigm, single-threaded, dynamic language, supporting object-oriented, imperative, and declarative (e.g. functional programming) styles¹.

JavaScript has many features and capabilities that make it a powerful and expressive language. Some of these include:

• Runtime object construction, variable parameter lists, function variables, dynamic script creation (via eval), object introspection (via for...in and Object utilities), and source-code recovery (JavaScript functions store their source text and can be retrieved through toString())¹.

• Data structures and types, such as arrays, objects, strings, numbers, booleans, symbols, BigInts, null, and undefined¹.

• Control flow and error handling mechanisms, such as if...else, switch, try...catch...finally, throw, and Error objects¹.

• Loops and iteration statements, such as for, while, do...while, continue, break, for...in, and for...of¹.

• Functions and functional programming features, such as defining functions, calling functions, function scope, closures, arguments and parameters, arrow functions, generators, async functions, and promises¹.

• Expressions and operators, such as assignment and comparison operators, arithmetic operators, bitwise and logical operators, conditional (ternary) operator, string concatenation operator (+), template literals (`), spread operator (...), destructuring assignment ({}, []), and optional chaining operator (?.)¹.

• Numbers and dates manipulation using the Number object, the Math object, and the Date object¹.

• Text formatting and manipulation using the String object and regular expressions¹.

• Indexed collections using arrays and typed arrays¹.

• Keyed collections using Map, WeakMap, Set, and WeakSet objects¹.

• Working with objects using the Object object and its methods¹.

• Inheritance and the prototype chain using the prototype property of objects¹.

• Classes and modules using the class and export/import keywords¹.

• Iterators and generators using the Symbol.iterator property of objects and the yield keyword¹.

• Asynchronous programming using callbacks, promises, async/await syntax¹.

• Meta-programming using proxies and reflection¹.