Object.getPrototypeOf()

The Object.getPrototypeOf() static method returns the prototype (i.e., the value of the internal [[Prototype]] property) of the specified object.

const prototype = {};
const object = Object.create(prototype);

console.log(Object.getPrototypeOf(object) === prototype);
// Expected output: true

Syntax

Object.getPrototypeOf(obj)

Parameters

• obj
  • : The object whose prototype is to be returned.

Return value

The prototype of the given object, which may be null.

Examples

Using getPrototypeOf

const proto = {};
const obj = Object.create(proto);
Object.getPrototypeOf(obj) === proto; // true

Non-object coercion

In ES5, it will throw a TypeError exception if the obj parameter isn’t an object. In ES2015, the parameter will be coerced to an Object.

Object.getPrototypeOf("foo");
// TypeError: "foo" is not an object (ES5 code)
Object.getPrototypeOf("foo");
// String.prototype                  (ES2015 code)

Specifications

Browser compatibility

See also

• Polyfill of Object.getPrototypeOf in core-js
• es-shims polyfill of Object.getPrototypeOf
• isPrototypeOf()
• setPrototypeOf()
• Object.prototype.__proto__
• getPrototypeOf()
• Object.getPrototypeOf by John Resig (2008)