Q208- How do you clone an object or array?

Cloning means creating a copy of an object or array.
There are two main types:

• Shallow clone → copies only the first level.
• Deep clone → copies all nested levels.

---

1️⃣ Cloning an Array

✅ Shallow Clone

• Using Spread Operator

  const arr = [1, 2, 3];
  const copy = [...arr];
  console.log(copy); // [1, 2, 3]
  

• Using slice()

  const arr = [1, 2, 3];
  const copy = arr.slice();
  

• Using Array.from()

  const copy = Array.from(arr);
  

✅ Deep Clone

For nested arrays:

const nested = [[1, 2], [3, 4]];
const deepCopy = JSON.parse(JSON.stringify(nested));

---

2️⃣ Cloning an Object

✅ Shallow Clone

• Using Spread Operator

  const obj = { a: 1, b: 2 };
  const copy = { ...obj };
  

• Using Object.assign()

  const copy = Object.assign({}, obj);
  

✅ Deep Clone

• Using JSON.parse(JSON.stringify())

  const deepObj = { a: 1, b: { c: 2 } };
  const deepCopy = JSON.parse(JSON.stringify(deepObj));
  

  ⚠️ Doesn’t work with functions, undefined, or special types like Date.

• Using Structured Clone (modern browsers)

  const deepCopy = structuredClone(deepObj);
  

---

💡 In Short:

• Shallow clone: ...obj, Object.assign(), or [...arr]
• Deep clone: JSON.parse(JSON.stringify(obj) or structuredClone()
  Use deep cloning when objects have nested data that should not reference the original.