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(<var>obj</var>)

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

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

Notes

In ES5, it will throw a TypeError exception if the obj parameter isn't an object. In ES6, the parameter will be coerced to an Object.

Object.getPrototypeOf("foo");
// TypeError: "foo" is not an object (ES5 code)
Object.getPrototypeOf("foo");
// String.prototype                  (ES6 code)

Specifications

Browser compatibility

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

• Object.prototype.isPrototypeOf()
• Object.setPrototypeOf()
• Object.prototype.__proto__
• John Resig's post on getPrototypeOf
• Reflect.getPrototypeOf()