StructuredClone

Deep Cloning in JavaScript with structuredClone

Copying JavaScript objects looks simple until values contain nested arrays, dates, maps, sets, typed arrays, or circular references. A shallow spread copies only the first level, while the old JSON.stringify and JSON.parse pattern changes or rejects several legitimate JavaScript values. structuredClone provides a standard deep-cloning operation based on the structured clone algorithm used by browser messaging APIs. Shallow copies keep nested references A spread expression creates a new outer object: