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    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 ❤️ and support.


    Install with npm:

    $ npm install --save is-descriptor


    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 = {}; = 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


    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



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

    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
    Building docs

    (This project's is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the 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:


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    Jon Schlinkert


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

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


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