Reflect.getOwnPropertyDescriptor()

The Reflect.getOwnPropertyDescriptor() static method is like Object.getOwnPropertyDescriptor(). It returns a property descriptor of the given property if it exists on the object, undefined otherwise.

Try it

const object = {
  property1: 42,
};

console.log(Reflect.getOwnPropertyDescriptor(object, "property1").value);
// Expected output: 42

console.log(Reflect.getOwnPropertyDescriptor(object, "property2"));
// Expected output: undefined

console.log(Reflect.getOwnPropertyDescriptor(object, "property1").writable);
// Expected output: true

Syntax

Reflect.getOwnPropertyDescriptor(target, propertyKey)

Parameters

target

The target object in which to look for the property.

propertyKey

The name of the property to get an own property descriptor for.

Return value

A property descriptor object if the property exists as an own property of target; otherwise, undefined.

Exceptions

TypeError

Thrown if target is not an object.

Description

Reflect.getOwnPropertyDescriptor() provides the reflective semantic of retrieving the property descriptor of an object. The only difference with Object.getOwnPropertyDescriptor() is how non-object targets are handled. Reflect.getOwnPropertyDescriptor() throws a TypeError if the target is not an object, while Object.getOwnPropertyDescriptor() coerces it to an object.

Reflect.getOwnPropertyDescriptor() invokes the [[GetOwnProperty]] object internal method of target.

Examples

Using Reflect.getOwnPropertyDescriptor()

Reflect.getOwnPropertyDescriptor({ x: "hello" }, "x");
// {value: "hello", writable: true, enumerable: true, configurable: true}

Reflect.getOwnPropertyDescriptor({ x: "hello" }, "y");
// undefined

Reflect.getOwnPropertyDescriptor([], "length");
// {value: 0, writable: true, enumerable: false, configurable: false}

Difference with Object.getOwnPropertyDescriptor()

If the target argument to this method is not an object (a primitive), then it will cause a TypeError. With Object.getOwnPropertyDescriptor, a non-object first argument will be coerced to an object at first.

Reflect.getOwnPropertyDescriptor("foo", 0);
// TypeError: "foo" is not non-null object

Object.getOwnPropertyDescriptor("foo", 0);
// { value: "f", writable: false, enumerable: true, configurable: false }

Specifications

Browser compatibility

See also

• Polyfill of Reflect.getOwnPropertyDescriptor in core-js
• Reflect
• Object.getOwnPropertyDescriptor()
• handler.getOwnPropertyDescriptor()