| # is-extendable [](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?" |
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| ## Install |
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| Install with [npm](https://www.npmjs.com/) |
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| ```sh |
| $ npm i is-extendable --save |
| ``` |
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| ## Usage |
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| ```js |
| var isExtendable = require('is-extendable'); |
| ``` |
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| Returns true if the value is any of the following: |
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| * `array` |
| * `regexp` |
| * `plain object` |
| * `function` |
| * `date` |
| * `error` |
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| ## Notes |
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| 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: |
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| * the value is not a primitive, or |
| * that the object is an `object`, `function` |
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| 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`. |
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| ## 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. |
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| ## Running tests |
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| Install dev dependencies: |
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| ```sh |
| $ npm i -d && npm test |
| ``` |
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| ## Contributing |
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| Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/is-extendable/issues/new) |
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| ## Author |
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| **Jon Schlinkert** |
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| + [github/jonschlinkert](https://github.com/jonschlinkert) |
| + [twitter/jonschlinkert](http://twitter.com/jonschlinkert) |
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| ## License |
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| Copyright © 2015 Jon Schlinkert |
| Released under the MIT license. |
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| *** |
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| _This file was generated by [verb-cli](https://github.com/assemble/verb-cli) on July 04, 2015._ |
