JS Built-ins
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ObjectObject.isFrozenintermediate

Object.isFrozen() — empty object after preventExtensions

📖 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() — empty + non-extensible = frozen

An empty object that has been made non-extensible is considered frozen, because there are no writable or configurable properties to violate the frozen constraint.

Challenge: Verify that an empty object after Object.preventExtensions is considered frozen.

💡 Hints (1)
  • • An empty non-extensible object trivially satisfies all frozen conditions