JS Practice — Built-in Objects

Object.isFrozen() — plain object

📖 Usage Example

// Check if an object is frozen
const obj = { a: 1 }
Object.isFrozen(obj)    // → false
Object.freeze(obj)
Object.isFrozen(obj)    // → true

Use Object.isFrozen() to verify that an object is fully immutable (no additions, deletions, or value changes allowed).

Object.isFrozen()

Object.isFrozen(obj) returns true if the object is non-extensible AND all its properties are non-configurable AND non-writable.

A plain object is not frozen by default.

Challenge: Implement checkFrozen(obj) that returns whether the object is frozen.

💡 Hints (1)