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:

sh
$ npm install --save is-data-descriptor

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'

About

<details> <summary><strong>Contributing</strong></summary>

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

</details>

<details> <summary><strong>Running Tests</strong></summary>

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

</details>

<details> <summary><strong>Building docs</strong></summary>

_(This project's readme.md is generated by verb, 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

</details>

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](https://github.com/jonschlinkert/is-accessor-descriptor "Returns true if a value has the characteristics of a valid JavaScript accessor descriptor.")
• 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: Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… more | [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: 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.")

Contributors

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright © 2017, Jon Schlinkert. Released under the [MIT License](LICENSE).

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