Object.defineProperties()

The Object.defineProperties() static method defines new or modifies existing properties directly on an object, returning the object.

{{InteractiveExample("JavaScript Demo: Object.defineProperties()")}}

```js interactive-example const object = {};

Object.defineProperties(object, { property1: { value: 42, writable: true, }, property2: {}, });

console.log(object.property1); // Expected output: 42

## Syntax

```js-nolint
Object.defineProperties(obj, props)

Parameters#

• obj
• : The object on which to define or modify properties.
• props

• : An object whose keys represent the names of properties to be defined or modified and whose values are objects describing those properties. Each value in props must be either a data descriptor or an accessor descriptor; it cannot be both (see {{jsxref("Object.defineProperty()")}} for more details).

  Data descriptors and accessor descriptors may optionally contain the following keys: - configurable - : true if and only if the type of this property descriptor may be changed and if the property may be deleted from the corresponding object. Defaults to false. - enumerable - : true if and only if this property shows up during enumeration of the properties on the corresponding object. Defaults to false.

  A data descriptor also has the following optional keys: - value - : The value associated with the property. Can be any valid JavaScript value (number, object, function, etc.). Defaults to {{jsxref("undefined")}}. - writable - : true if and only if the value associated with the property may be changed with an {{jsxref("Operators", "assignment operator", "assignment_operators", 1)}}. Defaults to false.

  An accessor descriptor also has the following optional keys: - get - : A function which serves as a getter for the property, or {{jsxref("undefined")}} if there is no getter. The function's return value will be used as the value of the property. Defaults to {{jsxref("undefined")}}. - set - : A function which serves as a setter for the property, or {{jsxref("undefined")}} if there is no setter. The function will receive as its only argument the new value being assigned to the property. Defaults to {{jsxref("undefined")}}.

  If a descriptor has neither of value, writable, get and set keys, it is treated as a data descriptor. If a descriptor has both value or writable and get or set keys, an exception is thrown.

Return value#

The object that was passed to the function.

Examples#

Using Object.defineProperties#

const obj = {};
Object.defineProperties(obj, {
  property1: {
    value: true,
    writable: true,
  },
  property2: {
    value: "Hello",
    writable: false,
  },
  // etc. etc.
});

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• Polyfill of Object.defineProperties in core-js
• es-shims polyfill of Object.defineProperties
• {{jsxref("Object.defineProperty()")}}
• {{jsxref("Object.keys()")}}
• Enumerability and ownership of properties