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Reflect.setPrototypeOf()

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

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The Reflect.setPrototypeOf() static method is like {{jsxref("Object.setPrototypeOf()")}} but returns a {{jsxref("Boolean")}}. It sets the prototype (i.e., the internal [[Prototype]] property) of a specified object.

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

```js interactive-example const object1 = {};

console.log(Reflect.setPrototypeOf(object1, Object.prototype)); // Expected output: true

console.log(Reflect.setPrototypeOf(object1, null)); // Expected output: true

const object2 = {};

console.log(Reflect.setPrototypeOf(Object.freeze(object2), null)); // Expected output: false

## Syntax

```js-nolint
Reflect.setPrototypeOf(target, prototype)

Parameters#

  • target
  • : The target object of which to set the prototype.
  • prototype
  • : The object's new prototype (an object or null).

Return value#

A {{jsxref("Boolean")}} indicating whether or not the prototype was successfully set.

Exceptions#

  • {{jsxref("TypeError")}}
  • : Thrown if target is not an object or if prototype is neither an object nor null.

Description#

Reflect.setPrototypeOf() provides the reflective semantic of setting the prototype of an object. At the very low level, setting the prototype returns a boolean (as is the case with the proxy handler). {{jsxref("Object.setPrototypeOf()")}} provides nearly the same semantic, but it throws a {{jsxref("TypeError")}} if the status is false (the operation was unsuccessful), while Reflect.setPrototypeOf() directly returns the status.

Reflect.setPrototypeOf() invokes the [[SetPrototypeOf]] object internal method of target.

Examples#

Using Reflect.setPrototypeOf()#

Reflect.setPrototypeOf({}, Object.prototype); // true

// It can change an object's [[Prototype]] to null.
Reflect.setPrototypeOf({}, null); // true

// Returns false if target is not extensible.
Reflect.setPrototypeOf(Object.freeze({}), null); // false

// Returns false if it cause a prototype chain cycle.
const target = {};
const proto = Object.create(target);
Reflect.setPrototypeOf(target, proto); // false

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#