JS Built-ins
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ObjectObject.getOwnPropertyDescriptorbeginner

Object.getOwnPropertyDescriptor() — check specific flags

📖 Usage Example
// Inspect a single property's descriptor
const obj = { x: 42 }
Object.getOwnPropertyDescriptor(obj, 'x')
// → { value: 42, writable: true, enumerable: true, configurable: true }

Use Object.getOwnPropertyDescriptor() to retrieve the descriptor object that describes a property's attributes.

Object.getOwnPropertyDescriptor() — inspecting flags

You can use the returned descriptor to check individual flags like enumerable and configurable.

Challenge: Implement isEnumerable(obj, key) that returns whether the own property key is enumerable.

isEnumerable({ a: 1 }, 'a')  // → true (normal property)
💡 Hints (2)
  • • Use optional chaining: `descriptor?.enumerable === true`.
  • • If the property does not exist, `undefined === true` is `false`.