Object.getPrototypeOf()

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

Syntax

Object.getPrototypeOf(obj)

Parameters

obj

The object whose prototype is to be returned.

Return value

The prototype of the given object. If there are no inherited properties, null is returned.

Examples

Using getPrototypeOf

var proto = {};
var 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

Specification
ECMAScript Language Specification
# sec-object.getprototypeof

Browser compatibility

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Opera-specific notes

Even though older Opera versions don't support Object.getPrototypeOf() yet, Opera supports the non-standard __proto__ property since Opera 10.50.

See also