javascript static method
Reflect.setPrototypeOf()
The Reflect.setPrototypeOf() static method is like setPrototypeOf() but returns a Boolean. It sets the prototype (i.e., the internal [[Prototype]] property) of a specified object.
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
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).
- : The object’s new prototype (an object or
Return value
A Boolean indicating whether or not the prototype was successfully set.
Exceptions
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). setPrototypeOf() provides nearly the same semantic, but it throws a 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