# for-in [](https://www.npmjs.com/package/for-in) [](https://npmjs.org/package/for-in) [](https://npmjs.org/package/for-in) [](https://travis-ci.org/jonschlinkert/for-in) > Iterate over the own and inherited enumerable properties of an object, and return an object with properties that evaluate to true from the callback. Exit early by returning `false`. JavaScript/Node.js ## Install Install with [npm](https://www.npmjs.com/): ```sh $ npm install --save for-in ``` ## Usage ```js var forIn = require('for-in'); var obj = {a: 'foo', b: 'bar', c: 'baz'}; var values = []; var keys = []; forIn(obj, function (value, key, o) { keys.push(key); values.push(value); }); console.log(keys); //=> ['a', 'b', 'c']; console.log(values); //=> ['foo', 'bar', 'baz']; ``` ## About ### Related projects * [arr-flatten](https://www.npmjs.com/package/arr-flatten): Recursively flatten an array or arrays. This is the fastest implementation of array flatten. | [homepage](https://github.com/jonschlinkert/arr-flatten "Recursively flatten an array or arrays. This is the fastest implementation of array flatten.") * [collection-map](https://www.npmjs.com/package/collection-map): Returns an array of mapped values from an array or object. | [homepage](https://github.com/jonschlinkert/collection-map "Returns an array of mapped values from an array or object.") * [for-own](https://www.npmjs.com/package/for-own): Iterate over the own enumerable properties of an object, and return an object with properties… [more](https://github.com/jonschlinkert/for-own) | [homepage](https://github.com/jonschlinkert/for-own "Iterate over the own enumerable properties of an object, and return an object with properties that evaluate to true from the callback. Exit early by returning `false`. JavaScript/Node.js.") ### Contributing Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new). ### Contributors | **Commits** | **Contributor** | | --- | --- | | 16 | [jonschlinkert](https://github.com/jonschlinkert) | | 2 | [paulirish](https://github.com/paulirish) | ### Building docs _(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_ To generate the readme, run the following command: ```sh $ npm install -g verbose/verb#dev verb-generate-readme && verb ``` ### Running tests Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command: ```sh $ npm install && npm test ``` ### Author **Jon Schlinkert** * [github/jonschlinkert](https://github.com/jonschlinkert) * [twitter/jonschlinkert](https://twitter.com/jonschlinkert) ### License Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert). Released under the [MIT License](LICENSE). *** _This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.4.2, on February 28, 2017._