<ul><li>JavaScript objects have internal systems to manage properties and optimize property access.</li><li>Objects with consistent sets of properties may have a 'hidden class' for faster property lookups.</li><li>JavaScript engines adjust internal structures based on object property changes.</li><li>Properties in JavaScript have hidden attributes like writable, enumerable, and configurable.</li><li>Property attributes can be inspected with methods like Object.getOwnPropertyDescriptor().</li><li>JavaScript properties can be accessed through the prototype chain, with the object's own property taking priority.</li><li>Object's non-enumerable properties are skipped in for...in loops.</li><li>Object.keys() method only lists an object's own enumerable properties, excluding inherited ones.</li><li>Object.getOwnPropertyNames() and Object.getOwnPropertySymbols() provide ways to access all properties.</li><li>Modern JavaScript engines follow a specific order when listing properties: integers, strings, then symbols.</li></ul>

Property Access and Enumeration in JavaScript Objects

Discover more