is-data-descriptor

What is is-data-descriptor?

The is-data-descriptor npm package is used to determine if an object is a valid data descriptor. Data descriptors are object keys that have attributes like value, writable, enumerable, and configurable. This package checks if a given object conforms to the specification of a data descriptor.

What are is-data-descriptor's main functionalities?

Check if an object is a data descriptor

This feature allows you to verify if a given object is a valid data descriptor by checking its properties and their respective values.

const isDataDescriptor = require('is-data-descriptor');

const descriptor = {value: 'value', writable: true, enumerable: true, configurable: true};
const result = isDataDescriptor(descriptor); // result is true

Other packages similar to is-data-descriptor

is-descriptor

This package is more general than is-data-descriptor. It checks if an object is any kind of descriptor, including data and accessor descriptors. It is a superset of is-data-descriptor functionality.

is-accessor-descriptor

Similar to is-data-descriptor, but specifically checks if an object is a valid accessor descriptor, which includes properties like get, set, enumerable, and configurable.

kind-of

While not limited to descriptors, this utility module can check the type of any JavaScript value, including whether it is a descriptor. It is more versatile but less specialized than is-data-descriptor.

README

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 :heart: and support.

Install

Install with npm:

$ npm install --save is-data-descriptor

Usage

var isDataDesc = require('is-data-descriptor');

Examples

true when the descriptor has valid properties with valid values.

// `value` can be anything
isDataDesc({value: 'foo'})
isDataDesc({value: function() {}})
isDataDesc({value: true})
//=> true

false when not an object

isDataDesc('a')
//=> false
isDataDesc(null)
//=> false
isDataDesc([])
//=> false

false when the object has invalid properties

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

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).

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

Contributing

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 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:

• is-accessor-descriptor: Returns true if a value has the characteristics of a valid JavaScript accessor descriptor. | homepage
• is-data-descriptor: Returns true if a value has the characteristics of a valid JavaScript data descriptor. | homepage
• is-descriptor: Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… more | homepage
• isobject: Returns true if the value is an object and not an array or null. | homepage

Contributors

Commits	Contributor
21	jonschlinkert
2	realityking

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright © 2017, Jon Schlinkert. Released under the MIT License.

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

Changelog

v2.0.0 - 2018-12-13

Commits

• refactor 8dcc492