javascript static method
Reflect.getOwnPropertyDescriptor()
The Reflect.getOwnPropertyDescriptor() static method is like getOwnPropertyDescriptor(). It returns a property descriptor of the given property if it exists on the object, undefined otherwise.
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
targetis not an object.
- : Thrown if
Description
Reflect.getOwnPropertyDescriptor() provides the reflective semantic of retrieving the property descriptor of an object. The only difference with 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 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 }