`Object.setPrototypeOf()`

Sets the prototype of a specified object to another object or null.

Since ES2015 Spec ↗

Syntax

Object.setPrototypeOf(obj, prototype)

Name	Type	Required	Description
`obj`	`object`	Yes	The object whose prototype is to be set.
`prototype`	`object \| null`	Yes	The new prototype, an object or null.

object — The same object that was passed in.

const proto = { greet() { return 'hi'; } };
const o = {};
Object.setPrototypeOf(o, proto);
console.log(o.greet());

Output

hi

const o = { a: 1 };
Object.setPrototypeOf(o, null);
console.log(Object.getPrototypeOf(o));

Output

null

Slow - changing an object's prototype deoptimizes property access in all engines. Prefer `Object.create` to set the prototype at creation time.