Define (or modify) an object property.
npm install @stdlib/utils-define-propertyWe believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js. The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases. When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there. To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
About stdlib...
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> [Define][mdn-define-property] (or modify) an object property.
``bash`
npm install @stdlib/utils-define-property
`javascript`
var defineProperty = require( '@stdlib/utils-define-property' );
#### defineProperty( obj, prop, descriptor )
[Defines][mdn-define-property] (or modifies) an object property.
`javascript
var obj = {};
defineProperty( obj, 'foo', {
'value': 'bar',
'writable': false
});
obj.foo = 'boop';
// throws
`
A property descriptor has the following optional properties:
- configurable: boolean indicating if property descriptor can be changed and if the property can be deleted from the provided object. Default: false.boolean
- enumerable: indicating if the property shows up when enumerating object properties. Default: false.boolean
- writable: indicating if the value associated with the property can be changed with an assignment operator. Default: false.function
- value: property value.
- get: which serves as a getter for the property, or, if no getter, undefined. When the property is accessed, a getter function is called without arguments and with the this context set to the object through which the property is accessed (which may not be the object on which the property is defined due to inheritance). The return value will be used as the property value. Default: undefined.function
- set: which serves as a setter for the property, or, if no setter, undefined. When assigning a property value, a setter function is called with one argument (the value being assigned to the property) and with the this context set to the object through which the property is assigned. Default: undefined.
- Property descriptors come in two flavors: data descriptors and accessor descriptors. A data descriptor is a property that has a value, which may or may not be writable. An accessor descriptor is a property described by a getter-setter function pair. A descriptor must be one of these two flavors and cannot be both.
`javascript
var defineProperty = require( '@stdlib/utils-define-property' );
function Foo( name ) {
if ( !(this instanceof Foo) ) {
return new Foo( name );
}
defineProperty( this, 'name', {
'value': name,
'configurable': true
});
return this;
}
var foo = new Foo( 'beep' );
try {
delete foo.name;
console.log( 'name property successfully deleted.' );`
} catch ( err ) {
console.error( err.message );
}
*
- [@stdlib/utils-define-properties][@stdlib/utils/define-properties]: define (and/or modify) object properties.
- [@stdlib/utils-define-read-only-property][@stdlib/utils/define-read-only-property]: define a read-only property.
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/utils-define-property.svg
[npm-url]: https://npmjs.org/package/@stdlib/utils-define-property
[test-image]: https://github.com/stdlib-js/utils-define-property/actions/workflows/test.yml/badge.svg?branch=v0.2.5
[test-url]: https://github.com/stdlib-js/utils-define-property/actions/workflows/test.yml?query=branch:v0.2.5
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-define-property/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/utils-define-property?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/utils-define-property/tree/deno
[deno-readme]: https://github.com/stdlib-js/utils-define-property/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/utils-define-property/tree/umd
[umd-readme]: https://github.com/stdlib-js/utils-define-property/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/utils-define-property/tree/esm
[esm-readme]: https://github.com/stdlib-js/utils-define-property/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/utils-define-property/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-define-property/main/LICENSE
[mdn-define-property]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty
[@stdlib/utils/define-properties]: https://www.npmjs.com/package/@stdlib/utils-define-properties
[@stdlib/utils/define-read-only-property]: https://www.npmjs.com/package/@stdlib/utils-define-read-only-property