Objects

A reference tour of the modern object surface — property descriptors, Object.freeze / seal / preventExtensions, Symbol-keyed properties and well-known symbols, the iterable protocol, structuredClone, Object.groupBy, and proxies.

A complete tour of ES6 classes — constructors, instance and static members, inheritance with extends and super, private fields and methods, getters and setters, and how every class still sits on top of the prototype chain.

A deep, practical explanation of JavaScript prototypes — what [[Prototype]] really is, how the prototype chain is searched, the difference between `__proto__` and `prototype`, Object.create, and how prototypes power inheritance under the surface of every class.

A practical introduction to JavaScript objects — literals, property access, shorthand syntax, computed keys, methods, mutation by reference, and the difference between value semantics and reference semantics.