Deep Clone an Object

📌 Definition:

📖 Detailed Explanation:

Spread and Object.assign are shallow. Use the built-in structuredClone() for a true deep copy. JSON.parse(JSON.stringify()) also deep-copies but drops functions/undefined and mangles Dates; a manual recursive clone handles custom cases.

💻 Solutions:

• JavaScript

// Modern built-in (best default):
const clone = structuredClone(obj);

// Manual recursive clone:
function deepClone(value) {
  if (value === null || typeof value !== 'object') return value;
  if (Array.isArray(value)) return value.map(deepClone);
  return Object.fromEntries(
    Object.entries(value).map(([k, v]) => [k, deepClone(v)])
  );
}

🔑 Key Points:

• structuredClone() is the modern deep-copy built-in
• Spread/Object.assign are SHALLOW (nested refs shared)
• JSON round-trip loses functions/undefined, breaks Dates
• Manual clone needed for class instances / special types

🌍 Real-World Example: