Object() constructor

The Object() constructor turns the input into an object. Its behavior depends on the input’s type.

Syntax

new Object()
new Object(value)

Object()
Object(value)

[!NOTE] Object() can be called with or without new, but sometimes with different effects. See Return value.

Parameters

• value Optional
  • : Any value.

Return value

When the Object() constructor itself is called or constructed, its return value is an object:

• If the value is null or undefined, it creates and returns an empty object.
• If the value is an object already, it returns the value.
• Otherwise, it returns an object of a type that corresponds to the given value. For example, passing a BigInt primitive returns a BigInt wrapper object.

When Object() is constructed but new.target is not the Object constructor itself, the behavior is slightly different — it initializes a new object with new.target.prototype as its prototype. Any argument value is ignored. This may happen, for example, when Object() is implicitly called via super() in the constructor of a class that extends Object. In this case, even if you pass a number to super(), the this value inside the constructor does not become a Number instance.

Examples

Creating a new Object

const o = new Object();
o.foo = 42;

console.log(o);
// { foo: 42 }

Using Object given undefined and null types

The following examples store an empty Object object in o:

const o = new Object();

const o = new Object(undefined);

const o = new Object(null);

Obtaining wrapper objects for BigInt and Symbol

The BigInt() and Symbol() constructors throw an error when called with new, to prevent the common mistake of creating a wrapper object instead of the primitive value. The only way to create a wrapper object for these types is to call Object() with them:

const numberObj = new Number(1);
console.log(typeof numberObj); // "object"

const bigintObj = Object(1n);
console.log(typeof bigintObj); // "object"

const symbolObj = Object(Symbol("foo"));
console.log(typeof symbolObj); // "object"

Specifications

Browser compatibility

See also

• Object initializer