JS Built-ins
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ObjectpropertyIsEnumerableintermediate

propertyIsEnumerable() — non-enumerable via defineProperty

📖 Usage Example
// Check if a property shows up in for...in loops
const obj = { a: 1 }
obj.propertyIsEnumerable('a')   // → true
Object.defineProperty(obj, 'b', { value: 2, enumerable: false })
obj.propertyIsEnumerable('b')   // → false

Use propertyIsEnumerable() to check whether a specific own property will appear during enumeration (e.g., for...in or Object.keys).

propertyIsEnumerable() — defineProperty

Properties created with Object.defineProperty and enumerable: false will return false from propertyIsEnumerable().

Challenge: Define a non-enumerable property and verify with propertyIsEnumerable().

💡 Hints (1)
  • • defineProperty defaults enumerable to false if not specified