text: # is-extendable [![NPM version](https://badge.fury.io/js/is-extendable.svg)](http://badge.fury.io/js/is-extendable)
  
  > Returns true if a value is any of the object types: array, regexp, plain object, function or date. This is useful for determining if a value can be extended, e.g. "can the value have keys?"
  
  ## Install
  
  Install with [npm](https://www.npmjs.com/)
  
  ```sh
  $ npm i is-extendable --save
  ```
  
  ## Usage
  
  ```js
  var isExtendable = require('is-extendable');
  ```
  
  Returns true if the value is any of the following:
  
  * `array`
  * `regexp`
  * `plain object`
  * `function`
  * `date`
  * `error`
  
  ## Notes
  
  All objects in JavaScript can have keys, but it's a pain to check for this, since we ether need to verify that the value is not `null` or `undefined` and:
  
  * the value is not a primitive, or
  * that the object is an `object`, `function`
  
  Also note that an `extendable` object is not the same as an [extensible object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible), which is one that (in es6) is not sealed, frozen, or marked as non-extensible using `preventExtensions`.
  
  ## Related projects
  
  * [assign-deep](https://github.com/jonschlinkert/assign-deep): Deeply assign the enumerable properties of source objects to a destination object.
  * [extend-shallow](https://github.com/jonschlinkert/extend-shallow): Extend an object with the properties of additional objects. node.js/javascript util.
  * [isobject](https://github.com/jonschlinkert/isobject): Returns true if the value is an object and not an array or null.
  * [is-plain-object](https://github.com/jonschlinkert/is-plain-object): Returns true if an object was created by the `Object` constructor.
  * [is-equal-shallow](https://github.com/jonschlinkert/is-equal-shallow): Does a shallow comparison of two objects, returning false if the keys or values differ.
  * [kind-of](https://github.com/jonschlinkert/kind-of): Get the native type of a value.
  
  ## Running tests
  
  Install dev dependencies:
  
  ```sh
  $ npm i -d && npm test
  ```
  
  ## Contributing
  
  Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/is-extendable/issues/new)
  
  ## Author
  
  **Jon Schlinkert**
  
  + [github/jonschlinkert](https://github.com/jonschlinkert)
  + [twitter/jonschlinkert](http://twitter.com/jonschlinkert)
  
  ## License
  
  Copyright © 2015 Jon Schlinkert
  Released under the MIT license.
  
  ***
  
  _This file was generated by [verb-cli](https://github.com/assemble/verb-cli) on July 04, 2015._