javascript

Generators are functions that can pause and resume execution using yield, producing values on demand. They implement the iterator protocol, enabling lazy evaluation, infinite sequences, and custom iteration with for...of.

JavaScript automatically manages memory through garbage collection using a mark-and-sweep algorithm — objects are freed when they become unreachable from root references, but common patterns like forgotten timers and detached DOM nodes cause memory leaks.

Proxy intercepts fundamental operations on objects (property access, assignment, function calls) through handler traps, while Reflect provides the default behavior for each trap — together they enable validation, reactive systems, and transparent wrappers.

Every JavaScript object has an internal [[Prototype]] link forming a chain — property lookups walk this chain until found or null. ES6 classes are syntactic sugar over this prototypal inheritance model.

CORS (Cross-Origin Resource Sharing) is a browser-enforced security mechanism that uses HTTP headers to control whether JavaScript on one origin can access resources from a different origin.