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# is-data-descriptor [](https://www.npmjs.com/package/is-data-descriptor) [](https://travis-ci.org/jonschlinkert/is-data-descriptor)
> Returns true if a value has the characteristics of a valid JavaScript data descriptor.
## Install
Install with [npm](https://www.npmjs.com/):
```sh
$ npm i is-data-descriptor --save
```
## Usage
```js
var isDataDesc = require('is-data-descriptor');
```
## Examples
`true` when the descriptor has valid properties with valid values.
```js
// `value` can be anything
isDataDesc({value: 'foo'})
isDataDesc({value: function() {}})
isDataDesc({value: true})
//=> true
```
`false` when not an object
```js
isDataDesc('a')
//=> false
isDataDesc(null)
//=> false
isDataDesc([])
//=> false
```
`false` when the object has invalid properties
```js
isDataDesc({value: 'foo', bar: 'baz'})
//=> false
isDataDesc({value: 'foo', bar: 'baz'})
//=> false
isDataDesc({value: 'foo', get: function(){}})
//=> false
isDataDesc({get: function(){}, value: 'foo'})
//=> false
```
`false` when a value is not the correct type
```js
isDataDesc({value: 'foo', enumerable: 'foo'})
//=> false
isDataDesc({value: 'foo', configurable: 'foo'})
//=> false
isDataDesc({value: 'foo', writable: 'foo'})
//=> false
```
## Valid properties
The only valid data descriptor properties are the following:
* `configurable` (required)
* `enumerable` (required)
* `value` (optional)
* `writable` (optional)
To be a valid data descriptor, either `value` or `writable` must be defined.
**Invalid properties**
A descriptor may have additional _invalid_ properties (an error will **not** be thrown).
```js
var foo = {};
Object.defineProperty(foo, 'bar', {
enumerable: true,
whatever: 'blah', // invalid, but doesn't cause an error
get: function() {
return 'baz';
}
});
console.log(foo.bar);
//=> 'baz'
```
## 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)
* [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://www.npmjs.com/package/is-descriptor) | [homepage](https://github.com/jonschlinkert/is-descriptor)
* [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)
## 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-data-descriptor/issues/new).
## Author
**Jon Schlinkert**
* [github/jonschlinkert](https://github.com/jonschlinkert)
* [twitter/jonschlinkert](http://twitter.com/jonschlinkert)
## License
Copyright © 2015 [Jon Schlinkert](https://github.com/jonschlinkert)
Released under the MIT license.
***
_This file was generated by [verb](https://github.com/verbose/verb) on December 28, 2015._
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