JS Practice — Built-in Objects

Object.isSealed() — plain object

📖 Usage Example

// Check if an object is sealed
const obj = { a: 1 }
Object.isSealed(obj)    // → false
Object.seal(obj)
Object.isSealed(obj)    // → true

Use Object.isSealed() to check whether an object's properties cannot be added or removed (though values may still change).

Object.isSealed()

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

A plain object is not sealed by default.

Challenge: Implement checkSealed(obj) that returns whether the object is sealed.

💡 Hints (1)