Object properties and attributes

Each object has a few properties. Each property, in turn, has a key and attributes. A property's state is stored in these attributes. All properties have the following attributes:

• Enumerable (boolean): This indicates if you can enumerate the properties of the object. System properties are non-enumerable while user properties are enumerable. Unless there is a strong reason, this property should remain untouched.

• Configurable(boolean): If this attribute is false, the property cannot be deleted or edited (it cannot change any of its attribute).

You can use the Object.getOwnPropertyDescriptor() method to retrieve an object's own properties:

    let obj = { 
      age: 25 
    } 
    console.log(Object.getOwnPropertyDescriptor(obj, 'age')); 
    //{"value":25,"writable":true,"enumerable":true,"configurable":true} 

Meanwhile, the property can be defined using the Object.defineProperty() method:

    let obj = { 
      age: 25 
  ...