README.md



is-data-descriptor    


Returns true if a value has the characteristics of a valid JavaScript data descriptor.


Please consider following this project's author, Jon Schlinkert, and consider starring the project to show your ❤ and support.


Install

Install with npm:

$ npm install --save is-data-descriptor


Usage

var isDataDesc = require('is-data-descriptor');


Examples

true when the descriptor has valid properties with valid values.

// `value` can be anything
isDataDesc({value: 'foo'})
isDataDesc({value: function() {}})
isDataDesc({value: true})
//=> true


false when not an object

isDataDesc('a')
//=> false
isDataDesc(null)
//=> false
isDataDesc([])
//=> false


false when the object has invalid properties

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

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).

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'


About


Contributing

Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).


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
```


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
```


Related projects

You might also be interested in these projects:


is-accessor-descriptor: Returns true if a value has the characteristics of a valid JavaScript accessor descriptor. | homepage


is-data-descriptor: Returns true if a value has the characteristics of a valid JavaScript data descriptor. | homepage


is-descriptor: Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… more | homepage


isobject: Returns true if the value is an object and not an array or null. | homepage


Contributors


Commits
Contributor


21
jonschlinkert


2
realityking


Author

Jon Schlinkert


github/jonschlinkert
twitter/jonschlinkert


License

Copyright © 2017, Jon Schlinkert.
Released under the MIT License.


This file was generated by verb-generate-readme, v0.6.0, on November 01, 2017.