🧊 Object.freeze() in JavaScript — Make Your Data Read-Only

In JavaScript, objects are mutable by default — which means you can change their properties any time.

But what if you want to protect your object from changes?

That’s where Object.freeze() comes in.

---

🧪 Basic Usage

jsCopyEditconst user = {
  name: "Nora",
  role: "Developer",
};

Object.freeze(user);

user.name = "Lina";  // ❌ Won't work
user.age = 25;       // ❌ Won't be added

console.log(user.name); // "Nora"
console.log(user.age);  // undefined

---

📌 Important Notes

• Object.freeze() makes an object immutable (no add, delete, or update).

• It only works on the top-level properties.

• Nested objects are not frozen!

jsCopyEditconst data = {
  info: {
    city: "Gaza",
  },
};

Object.freeze(data);

data.info.city = "Ramallah"; // ✅ Still works!

console.log(data.info.city); // "Ramallah"

To deeply freeze an object, you need a helper function (e.g., recursive freeze).

---

🧠 When to Use It

• 🔐 Prevent accidental data mutations

• 🧪 Ensure constant config objects stay unchanged

• 🔍 Improve code predictability and debugging

---

✅ Summary

• Object.freeze() = shallow immutability

• Use it to lock down objects

• Be careful with nested structures