JavaScript: Property Attributes: enumerable, configurable, writable, value

Property Attributes

Each property has associated info called attribute.

The attributes specify the property value, whether it can be changed, or whether it can be enumerated of function that go thru them.

Data Property Attributes

value

The property's value.

writable

When true, the property's value can be changed.

enumerable

When true, the property shows in some enumeration constructs, such as for-in Loop. [see JavaScript: List Properties]

configurable

If false, you can't delete the property, nor change the property attributes (example: make it configurable again), nor change it to/from get/set property. But you may still change the value.

Accessor Property's Attributes

Getter/Setter Properties

Show Property Attributes

• Object.getOwnPropertyDescriptor
• Reflect.getOwnPropertyDescriptor
• Object.prototype.propertyIsEnumerable

Set Property Attributes

• Reflect.defineProperty
• Object.defineProperty
• Object.defineProperties