Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.
Install
Install with npm:
$ npm install --save is-descriptor
Usage
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.
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
isDescriptor('a');
//=> false
isDescriptor(null);
//=> false
isDescriptor([]);
//=> false
data descriptor
true
when the object has valid properties with valid values.
isDescriptor({value: 'foo'});
//=> true
isDescriptor({value: noop});
//=> true
false
when the object has invalid properties
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
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.
isDescriptor({get: noop, set: noop});
//=> true
isDescriptor({get: noop});
//=> true
isDescriptor({set: noop});
//=> true
false
when the object has invalid properties
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
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
isDescriptor({get: noop, set: noop, enumerable: 'foo'});
//=> false
isDescriptor({set: noop, configurable: 'foo'});
//=> false
isDescriptor({get: noop, configurable: 'foo'});
//=> false
About
Related projects
Contributing
Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
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 readme template.)_
To generate the readme, run the following command:
$ 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:
$ npm install && npm test
Author
Jon Schlinkert
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.