Return an array of an object's own enumerable property names.
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> Return an array of an object's own enumerable property names.
``bash`
npm install @stdlib/utils-keys
`javascript`
var objectKeys = require( '@stdlib/utils-keys' );
#### objectKeys( obj )
Returns an array of an object's own enumerable property names.
`javascript
var obj = {
'a': 1,
'b': 2
};
var keys = objectKeys( obj );
// e.g., returns [ 'a', 'b' ]
`
- 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.Object.keys()
- In contrast to the built-in , if provided null or undefined, the function returns an empty array, rather than throwing an error.
`javascript
var objectKeys = require( '@stdlib/utils-keys' );
function Foo() {
this.beep = 'boop';
this.a = {
'b': 'c'
};
return this;
}
Foo.prototype.foo = [ 'bar' ];
var obj = new Foo();
var keys = objectKeys( obj );
console.log( keys );
// e.g., => [ 'beep', 'a' ]
`
*
- [@stdlib/utils-entries][@stdlib/utils/entries]: return an array of an object's own enumerable property key-value pairs.
- [@stdlib/utils-keys-in][@stdlib/utils/keys-in]: return an array of an object's own and inherited enumerable property names.
- [@stdlib/utils-nonindex-keys][@stdlib/utils/nonindex-keys]: return an array of an object's own enumerable property names which are not integer indices.
- [@stdlib/utils-values][@stdlib/utils/values]: return an array of an object's own enumerable property values.
*
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].
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---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[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-keys/tree/deno
[deno-readme]: https://github.com/stdlib-js/utils-keys/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/utils-keys/tree/umd
[umd-readme]: https://github.com/stdlib-js/utils-keys/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/utils-keys/tree/esm
[esm-readme]: https://github.com/stdlib-js/utils-keys/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/utils-keys/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-keys/main/LICENSE
[ecma-262-for-in]: https://262.ecma-international.org/5.1/#sec-12.6.4
[@stdlib/utils/entries]: https://www.npmjs.com/package/@stdlib/utils-entries
[@stdlib/utils/keys-in]: https://www.npmjs.com/package/@stdlib/utils-keys-in
[@stdlib/utils/nonindex-keys]: https://www.npmjs.com/package/@stdlib/utils-nonindex-keys
[@stdlib/utils/values]: https://www.npmjs.com/package/@stdlib/utils-values