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:

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: 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.")

Contributing

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

Contributors

Building docs

_(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

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
• 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 July 22, 2017._