Which answer is correct?

Use `structuredClone(obj)`. It's a built-in function that handles nested objects, arrays, Maps, Sets, Dates, RegExps, and circular references.

— modern_js

Use `JSON.parse(JSON.stringify(obj))`. It creates a deep copy by serializing and deserializing.

— json_trick

Use `Object.assign({}, obj)` or `{...obj}`. The spread operator copies all properties.

— spread_fan

Use lodash `_.cloneDeep(obj)`. It handles all edge cases.

— lodash_user