JavaScript Reflect.defineProperty() Method

The static method Reflect.defineProperty() allows the precise addition to or modification of a property on an object. The Reflect.defineProperty() method returns a Boolean value which indicates that whether or not the property was successfully defined.

Syntax

Parameter

target: It is the target object which defines the property.

propertyKey: It is the name of the property to be defined or modified.

Attributes: It is the attributes for the property being defined or modified.

Return value:

This method returns a Boolean value which indicates that whether or not the property was successfully defined.

Exceptions

This exception will throw a TypeError if the target is not an Object.

Example 1

const u = {};
const result = Reflect.defineProperty(u, "p",
{ value : 6,});
console.log( u ); 

Output:

Object {  }

Example 2

const u = {};
const su = Reflect.defineProperty(u, "p",
{ value : 3,
  writable: true,
 //write 
 // enumerable: true,
 //configurable: true
}
);
console.log( u );
console.log( su);

Output:

 Object {  }
  true

Example 3

const object1 = {};
const object2 = {};
(Reflect.defineProperty(object2, 'property2', {value: 12}))
if (Reflect.defineProperty(object1, 'property1', {value: 42})) {
  console.log('property1 created!');
} else {
  console.log('problem creating property1');
}
console.log(object1.property1);
console.log(object2.property2);

Output: