# propertyNames
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return an array of an object's own enumerable and non-enumerable property names.
## Installation
```bash
npm install @stdlib/utils-property-names
```
## Usage
```javascript
var propertyNames = require( '@stdlib/utils-property-names' );
```
#### propertyNames( obj )
Returns an `array` of an object's own enumerable and non-enumerable property names.
```javascript
var obj = {
'a': 1,
'b': 2
};
var keys = propertyNames( obj );
// e.g., returns [ 'a', 'b' ]
```
## Notes
- Name order is not guaranteed, as `object` key enumeration is not specified according to the [ECMAScript specification][ecma-262-for-in]. In practice, however, most engines use insertion order to sort an `object`'s keys, thus allowing for deterministic extraction.
- In contrast to the built-in `Object.getOwnPropertyNames()`, if provided `null` or `undefined`, the function returns an empty `array`, rather than throwing an error.
## Examples
```javascript
var defineProperty = require( '@stdlib/utils-define-property' );
var propertyNames = require( '@stdlib/utils-property-names' );
function Foo() {
this.beep = 'boop';
this.a = {
'b': 'c'
};
defineProperty( this, 'baz', {
'value': 'qux',
'configurable': true,
'writable': true,
'enumerable': false
});
return this;
}
Foo.prototype.foo = [ 'bar' ];
var obj = new Foo();
var keys = propertyNames( obj );
console.log( keys );
// e.g., => [ 'beep', 'a', 'baz' ]
```
* * *
## Notice
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]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2022. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/utils-property-names.svg
[npm-url]: https://npmjs.org/package/@stdlib/utils-property-names
[test-image]: https://github.com/stdlib-js/utils-property-names/actions/workflows/test.yml/badge.svg
[test-url]: https://github.com/stdlib-js/utils-property-names/actions/workflows/test.yml
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-property-names/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/utils-property-names?branch=main
[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-property-names/tree/deno
[umd-url]: https://github.com/stdlib-js/utils-property-names/tree/umd
[esm-url]: https://github.com/stdlib-js/utils-property-names/tree/esm
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://gitter.im/stdlib-js/stdlib/
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-property-names/main/LICENSE
[ecma-262-for-in]: http://www.ecma-international.org/ecma-262/5.1/#sec-12.6.4
[@stdlib/utils/keys]: https://www.npmjs.com/package/@stdlib/utils-keys
[@stdlib/utils/nonenumerable-property-names]: https://www.npmjs.com/package/@stdlib/utils-nonenumerable-property-names
[@stdlib/utils/property-names-in]: https://www.npmjs.com/package/@stdlib/utils-property-names-in
[@stdlib/utils/property-symbols]: https://www.npmjs.com/package/@stdlib/utils-property-symbols