===== ISTEM =====
Solve the following programming task.

TASK: Deep Clone an Object

Write a function 'deepClone(obj)' that deeply copies a given JavaScript object or array (including nested objects, arrays and primitives) without sharing references. It must also clone Date and RegExp objects.

STARTER CODE (javascript):
function deepClone(obj) {
  // Write your code here
}

module.exports = { deepClone };


RULES:
- Keep the function name and signature EXACTLY as given.
- Return working code only. No explanations.
- Put the code in a single ``` block.
- Try to solve it first. If you genuinely cannot, write only this single
  line instead of producing faulty code: CANNOT_SOLVE

===== HAM YANIT =====
```javascript
function deepClone(obj) {
  const seen = new WeakMap();

  function clone(value) {
    if (value === null || typeof value !== "object") {
      return value;
    }

    if (seen.has(value)) {
      return seen.get(value);
    }

    let copy;

    if (value instanceof Date) {
      copy = new Date(value.getTime());
    } else if (value instanceof RegExp) {
      copy = new RegExp(value.source, value.flags);
    } else if (Array.isArray(value)) {
      copy = [];
    } else {
      copy = Object.create(Object.getPrototypeOf(value));
    }

    seen.set(value, copy);

    for (const key of Reflect.ownKeys(value)) {
      const descriptor = Object.getOwnPropertyDescriptor(value, key);

      if ("value" in descriptor) {
        descriptor.value = clone(descriptor.value);
      }

      Object.defineProperty(copy, key, descriptor);
    }

    return copy;
  }

  return clone(obj);
}

module.exports = { deepClone };
```