30Implement deep clone with circular references, Map, Set, and Date

Implement deepClone(value). It returns a copy where every nested object is new, so changing the copy never changes the original.

const original = { tags: new Set(["a"]), meta: new Map([["created", new Date(0)]]) };
original.self = original;

const copy = deepClone(original);
copy.self === copy; // true: the cycle is preserved inside the copy
copy.meta.get("created") === original.meta.get("created"); // false: new Date

Requirements

• Clone plain objects and arrays deeply.
• Clone Date, RegExp, Map (keys and values) and Set.
• Handle circular references, and keep shared references shared: if the original uses one object twice, the copy uses one cloned object twice.
• Keep the prototype, so a class instance stays an instance of its class.
• Copy own enumerable symbol keys too.
• Return primitives and functions as they are.