Reflect.getOwnPropertyDescriptor()
The static
Reflect.getOwnPropertyDescriptor()
method is similar to
Object.getOwnPropertyDescriptor()
. It returns a property descriptor of
the given property if it exists on the object, undefined
otherwise.
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 in target
object; otherwise, undefined
.
Exceptions
Description
The Reflect.getOwnPropertyDescriptor
method returns a property descriptor
of the given property if it exists in the target
object,
undefined
otherwise. The only difference to
Object.getOwnPropertyDescriptor()
is how non-object targets are handled.
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 to 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
Specification |
---|
ECMAScript Language Specification # sec-reflect.getownpropertydescriptor |
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