JavaScript (ES2026) reference · Object Methods

JavaScript Object.getPrototypeOf() Method

Return the prototype of an object: the object it inherits methods and properties from, or null.

JavaScript (ES2026) Since ES5

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Syntax

Object.getPrototypeOf(obj)

Parameter	Description
`obj`	The object to inspect or change.

The prototype object, or null.

Built-in prototypesTry it yourself

console.log(Object.getPrototypeOf([]) === Array.prototype, Object.getPrototypeOf({}) === Object.prototype);

Output

true true

Class inheritanceTry it yourself

class Animal {}
class Dog extends Animal {}
console.log(Object.getPrototypeOf(Dog.prototype) === Animal.prototype);

Output

true

Version	Change
JavaScript ES5	Added

Object.setPrototypeOf() · Change the prototype of an existing object. It is slow in most engines; prefer Object.create() or classes.
Object.create() · Create a new object with the given prototype (or null for an object with no inherited properties at all).
JavaScript Objects · tutorial