is-descriptor
Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.
Last updated 5 years ago by jonschlinkert .
MIT · Repository · Bugs · Original npm · Tarball · package.json
$ cnpm install is-descriptor 
SYNC missed versions from official npm registry.

is-descriptor NPM version NPM monthly downloads NPM total downloads Linux Build Status

Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.

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

Install

Install with npm:

$ npm install --save is-descriptor

Usage

const 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.

const obj = {};
obj.foo = null;

Object.defineProperty(obj, 'bar', { value: 'xyz' });
Reflect.defineProperty(obj, 'baz', { value: 'xyz' });

isDescriptor(obj, 'foo'); //=> true
isDescriptor(obj, 'bar'); //=> true
isDescriptor(obj, 'baz'); //=> true

Examples

value type

Returns false when not an object

isDescriptor('a'); //=> false
isDescriptor(null); //=> false
isDescriptor([]); //=> false

data descriptor

Returns true when the object has valid properties with valid values.

isDescriptor({ value: 'foo' }); //=> true
isDescriptor({ value: function() {} }); //=> true

Returns false when the object has invalid properties

isDescriptor({ value: 'foo', bar: 'baz' }); //=> false
isDescriptor({ value: 'foo', bar: 'baz' }); //=> false
isDescriptor({ value: 'foo', get: function() {} }); //=> false
isDescriptor({ get: function() {}, value: function() {} }); //=> 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: function() {}, set: function() {} }); //=> true
isDescriptor({ get: function() {} }); //=> true
isDescriptor({ set: function() {} }); //=> true

false when the object has invalid properties

isDescriptor({ get: function() {}, set: function() {}, bar: 'baz' }); //=> false
isDescriptor({ get: function() {}, writable: true }); //=> false
isDescriptor({ get: function() {}, value: true }); //=> false

Returns false when an accessor is not a function

isDescriptor({ get: function() {}, set: 'baz' }); //=> false
isDescriptor({ get: 'foo', set: function() {} }); //=> false
isDescriptor({ get: 'foo', bar: 'baz' }); //=> false
isDescriptor({ get: 'foo', set: 'baz' }); //=> false

Returns false when a value is not the correct type

isDescriptor({ get: function() {}, set: function() {}, enumerable: 'foo' }); //=> false
isDescriptor({ set: function() {}, configurable: 'foo' }); //=> false
isDescriptor({ get: function() {}, configurable: 'foo' }); //=> false

About

<summary> Contributing</summary>

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

<summary> Running Tests</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:

$ npm install && npm test
<summary> Building docs</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 readme template.)

To generate the readme, run the following command:

$ npm install -g verbose/verb#dev verb-generate-readme && verb

Related projects

You might also be interested in these projects:

Contributors

Commits Contributor
33 jonschlinkert
1 doowb
1 realityking
1 wtgtybhertgeghgtwtg

Author

Jon Schlinkert

License

Copyright © 2018, Jon Schlinkert. Released under the MIT License.


This file was generated by verb-generate-readme, v0.8.0, on December 13, 2018.

Current Tags

  • 0.1.6                                ...           bugfix (3 years ago)
  • 3.0.0                                ...           latest (2 years ago)

11 Versions

  • 3.0.0                                ...           2 years ago
  • 1.0.2                                ...           3 years ago
  • 0.1.6                                ...           3 years ago
  • 1.0.1                                ...           3 years ago
  • 1.0.0                                ...           3 years ago
  • 0.1.5                                ...           3 years ago
  • 0.1.4                                ...           5 years ago
  • 0.1.3                                ...           5 years ago
  • 0.1.2                                ...           5 years ago
  • 0.1.1                                ...           5 years ago
  • 0.1.0                                ...           5 years ago
Maintainers (1)
Downloads
Today 50,654
This Week 154,259
This Month 218,151
Last Day 103,605
Last Week 582,036
Last Month 2,635,664
Dependencies (4)
Dev Dependencies (1)
Dependents (71)

Copyright 2014 - 2016 © taobao.org |