Object.defineProperties()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

Try it

const object1 = {};

Object.defineProperties(object1, {
  property1: {
    value: 42,
    writable: true,
  },
  property2: {},
});

console.log(object1.property1);
// Expected output: 42

Syntax

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 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 undefined.
writable: true if and only if the value associated with the property may be changed with an assignment operator. Defaults to false.

An accessor descriptor also has the following optional keys:

get: A function which serves as a getter for the property, or undefined if there is no getter. The function's return value will be used as the value of the property. Defaults to undefined.