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.
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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
A TypeError
, if target
is not an Object
.
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 (ECMA-262) The definition of 'Reflect.getOwnPropertyDescriptor' in that specification. |
Browser compatibility
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
getOwnPropertyDescriptor | Chrome Full support 49 | Edge Full support 12 | Firefox Full support 42 | IE No support No | Opera Full support 36 | Safari Full support 10 | WebView Android Full support 49 | Chrome Android Full support 49 | Firefox Android Full support 42 | Opera Android Full support 36 | Safari iOS Full support 10 | Samsung Internet Android Full support 5.0 | nodejs Full support 6.0.0 |
Legend
- Full support
- Full support
- No support
- No support