17th of 20 Questions.
What is the Structured Clone Algorithm? How is it different from JSON serialization? What types can and cannot be cloned?
Structured cloning copies complex objects recursively, preserving cycles and supporting more types than JSON (e.g., Map, Set, Date, RegExp). Cannot clone Function, DOM nodes, Error objects.
postMessage uses structured clone, which handles cyclical references, typed arrays, and many built-in objects. JSON serialization fails on cycles and unsupported types (e.g., undefined, Map, Set). Structured clone is more powerful but cannot clone functions, DOM elements, or certain system objects.