Documentación offline JavaScript main
/ ó ⌘K

Reflect.ownKeys()

main Documentación oficial Licencia CC-BY-SA-2.5Descargado el 2026-08-02

En esta página

The Reflect.ownKeys() static method returns an array of the target object's own property keys.

{{InteractiveExample("JavaScript Demo: Reflect.ownKeys()")}}

```js interactive-example const object = { property1: 42, property2: 13, };

const array = [];

console.log(Reflect.ownKeys(object)); // Expected output: Array ["property1", "property2"]

console.log(Reflect.ownKeys(array)); // Expected output: Array ["length"]

## Syntax

```js-nolint
Reflect.ownKeys(target)

Parameters#

  • target
  • : The target object from which to get the own keys.

Return value#

An {{jsxref("Array")}} of the target object's own property keys, including strings and symbols. For most objects, the array will be in the order of:

  1. Non-negative integer indexes in increasing numeric order (but as strings)
  2. Other string keys in the order of property creation
  3. Symbol keys in the order of property creation.

Exceptions#

  • {{jsxref("TypeError")}}
  • : Thrown if target is not an object.

Description#

Reflect.ownKeys() provides the reflective semantic of retrieving all property keys of an object. It is the only way to get all own properties – enumerable and not enumerable, strings and symbols — in one call, without extra filtering logic. For example, {{jsxref("Object.getOwnPropertyNames()")}} takes the return value of Reflect.ownKeys() and filters to only string values, while {{jsxref("Object.getOwnPropertySymbols()")}} filters to only symbol values. Because normal objects implement [[OwnPropertyKeys]] to return all string keys before symbol keys, Reflect.ownKeys(target) is usually equivalent to Object.getOwnPropertyNames(target).concat(Object.getOwnPropertySymbols(target)). However, if the object has a custom [[OwnPropertyKeys]] method (such as through a proxy's ownKeys handler), the order of the keys may be different.

Reflect.ownKeys() invokes the [[OwnPropertyKeys]] object internal method of target.

Examples#

Using Reflect.ownKeys()#

Reflect.ownKeys({ z: 3, y: 2, x: 1 }); // [ "z", "y", "x" ]
Reflect.ownKeys([]); // ["length"]

const sym = Symbol.for("comet");
const sym2 = Symbol.for("meteor");
const obj = {
  [sym]: 0,
  str: 0,
  773: 0,
  0: 0,
  [sym2]: 0,
  "-1": 0,
  8: 0,
  "second str": 0,
};
Reflect.ownKeys(obj);
// [ "0", "8", "773", "str", "-1", "second str", Symbol(comet), Symbol(meteor) ]
// Indexes in numeric order,
// strings in insertion order,
// symbols in insertion order

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#