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- # is-descriptor [![NPM version](https://img.shields.io/npm/v/is-descriptor.svg?style=flat)](https://www.npmjs.com/package/is-descriptor) [![NPM monthly downloads](https://img.shields.io/npm/dm/is-descriptor.svg?style=flat)](https://npmjs.org/package/is-descriptor) [![NPM total downloads](https://img.shields.io/npm/dt/is-descriptor.svg?style=flat)](https://npmjs.org/package/is-descriptor) [![Linux Build Status](https://img.shields.io/travis/jonschlinkert/is-descriptor.svg?style=flat&label=Travis)](https://travis-ci.org/jonschlinkert/is-descriptor)
-
- > Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.
-
- ## Install
-
- Install with [npm](https://www.npmjs.com/):
-
- ```sh
- $ npm install --save is-descriptor
- ```
-
- ## Usage
-
- ```js
- var isDescriptor = require('is-descriptor');
-
- isDescriptor({value: 'foo'})
- //=> true
- isDescriptor({get: function(){}, set: function(){}})
- //=> true
- isDescriptor({get: 'foo', set: function(){}})
- //=> false
- ```
-
- You may also check for a descriptor by passing an object as the first argument and property name (`string`) as the second argument.
-
- ```js
- var obj = {};
- obj.foo = 'abc';
-
- Object.defineProperty(obj, 'bar', {
- value: 'xyz'
- });
-
- isDescriptor(obj, 'foo');
- //=> true
- isDescriptor(obj, 'bar');
- //=> true
- ```
-
- ## Examples
-
- ### value type
-
- `false` when not an object
-
- ```js
- isDescriptor('a');
- //=> false
- isDescriptor(null);
- //=> false
- isDescriptor([]);
- //=> false
- ```
-
- ### data descriptor
-
- `true` when the object has valid properties with valid values.
-
- ```js
- isDescriptor({value: 'foo'});
- //=> true
- isDescriptor({value: noop});
- //=> true
- ```
-
- `false` when the object has invalid properties
-
- ```js
- isDescriptor({value: 'foo', bar: 'baz'});
- //=> false
- isDescriptor({value: 'foo', bar: 'baz'});
- //=> false
- isDescriptor({value: 'foo', get: noop});
- //=> false
- isDescriptor({get: noop, value: noop});
- //=> false
- ```
-
- `false` when a value is not the correct type
-
- ```js
- isDescriptor({value: 'foo', enumerable: 'foo'});
- //=> false
- isDescriptor({value: 'foo', configurable: 'foo'});
- //=> false
- isDescriptor({value: 'foo', writable: 'foo'});
- //=> false
- ```
-
- ### accessor descriptor
-
- `true` when the object has valid properties with valid values.
-
- ```js
- isDescriptor({get: noop, set: noop});
- //=> true
- isDescriptor({get: noop});
- //=> true
- isDescriptor({set: noop});
- //=> true
- ```
-
- `false` when the object has invalid properties
-
- ```js
- isDescriptor({get: noop, set: noop, bar: 'baz'});
- //=> false
- isDescriptor({get: noop, writable: true});
- //=> false
- isDescriptor({get: noop, value: true});
- //=> false
- ```
-
- `false` when an accessor is not a function
-
- ```js
- isDescriptor({get: noop, set: 'baz'});
- //=> false
- isDescriptor({get: 'foo', set: noop});
- //=> false
- isDescriptor({get: 'foo', bar: 'baz'});
- //=> false
- isDescriptor({get: 'foo', set: 'baz'});
- //=> false
- ```
-
- `false` when a value is not the correct type
-
- ```js
- isDescriptor({get: noop, set: noop, enumerable: 'foo'});
- //=> false
- isDescriptor({set: noop, configurable: 'foo'});
- //=> false
- isDescriptor({get: noop, configurable: 'foo'});
- //=> false
- ```
-
- ## About
-
- ### Related projects
-
- * [is-accessor-descriptor](https://www.npmjs.com/package/is-accessor-descriptor): Returns true if a value has the characteristics of a valid JavaScript accessor descriptor. | [homepage](https://github.com/jonschlinkert/is-accessor-descriptor "Returns true if a value has the characteristics of a valid JavaScript accessor descriptor.")
- * [is-data-descriptor](https://www.npmjs.com/package/is-data-descriptor): Returns true if a value has the characteristics of a valid JavaScript data descriptor. | [homepage](https://github.com/jonschlinkert/is-data-descriptor "Returns true if a value has the characteristics of a valid JavaScript data descriptor.")
- * [is-descriptor](https://www.npmjs.com/package/is-descriptor): Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… [more](https://github.com/jonschlinkert/is-descriptor) | [homepage](https://github.com/jonschlinkert/is-descriptor "Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.")
- * [isobject](https://www.npmjs.com/package/isobject): Returns true if the value is an object and not an array or null. | [homepage](https://github.com/jonschlinkert/isobject "Returns true if the value is an object and not an array or null.")
-
- ### Contributing
-
- Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
-
- ### Contributors
-
- | **Commits** | **Contributor** |
- | --- | --- |
- | 24 | [jonschlinkert](https://github.com/jonschlinkert) |
- | 1 | [doowb](https://github.com/doowb) |
- | 1 | [wtgtybhertgeghgtwtg](https://github.com/wtgtybhertgeghgtwtg) |
-
- ### 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), v0.6.0, on July 22, 2017._
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