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- # is-data-descriptor <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
- [![github actions][actions-image]][actions-url]
- [![coverage][codecov-image]][codecov-url]
- [![License][license-image]][license-url]
- [![Downloads][downloads-image]][downloads-url]
- [![npm badge][npm-badge-png]][package-url]
- > Returns true if a value has the characteristics of a valid JavaScript data descriptor.
- ## Install
- Install with [npm](https://npmjs.com/):
- ```sh
- $ npm install --save is-data-descriptor
- ```
- ## Usage
- ```js
- var isDataDesc = require('is-data-descriptor');
- var assert = require('assert');
- ```
- ## Examples
- `true` when the descriptor has valid properties with valid values.
- ```js
- // `value` can be anything
- assert.equal(isDataDesc({ value: 'foo' }), true);
- assert.equal(isDataDesc({ value: function () {} }), true);
- assert.equal(isDataDesc({ value: true }), true);
- ```
- `false` when not an object
- ```js
- assert.equal(isDataDesc('a'), false);
- assert.equal(isDataDesc(null), false);
- ```
- `false` when the object has invalid properties
- ```js
- assert.equal(isDataDesc({ value: 'foo', enumerable: 'baz' }), false);
- assert.equal(isDataDesc({ value: 'foo', configurable: 'baz' }), false);
- assert.equal(isDataDesc({ value: 'foo', get() {} }), false);
- assert.equal(isDataDesc({ get() {}, value: 'foo' }), false);
- ```
- `false` when a value is not the correct type
- ```js
- assert.equal(isDataDesc({ value: 'foo', enumerable: 'foo' }), false);
- assert.equal(isDataDesc({ value: 'foo', configurable: 'foo' }), false);
- assert.equal(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).
- ```js
- var foo = {};
- Object.defineProperty(foo, 'bar', {
- enumerable: true,
- whatever: 'blah', // invalid, but doesn't cause an error
- get() {
- return 'baz';
- }
- });
- assert.equal(foo.bar, 'baz');
- ```
- ### Related projects
- You might also be interested in these projects:
- * [is-accessor-descriptor](https://npmjs.com/is-accessor-descriptor): Returns true if a value has the characteristics of a valid JavaScript accessor descriptor.
- * [is-descriptor](https://npmjs.com/is-descriptor): Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… [more](https://npmjs.com/is-descriptor)
- [package-url]: https://npmjs.org/package/is-data-descriptor
- [npm-version-svg]: https://versionbadg.es/inspect-js/is-data-descriptor.svg
- [deps-svg]: https://david-dm.org/inspect-js/is-data-descriptor.svg
- [deps-url]: https://david-dm.org/inspect-js/is-data-descriptor
- [dev-deps-svg]: https://david-dm.org/inspect-js/is-data-descriptor/dev-status.svg
- [dev-deps-url]: https://david-dm.org/inspect-js/is-data-descriptor#info=devDependencies
- [npm-badge-png]: https://nodei.co/npm/is-data-descriptor.png?downloads=true&stars=true
- [license-image]: https://img.shields.io/npm/l/is-data-descriptor.svg
- [license-url]: LICENSE
- [downloads-image]: https://img.shields.io/npm/dm/is-data-descriptor.svg
- [downloads-url]: https://npm-stat.com/charts.html?package=is-data-descriptor
- [codecov-image]: https://codecov.io/gh/inspect-js/is-data-descriptor/branch/main/graphs/badge.svg
- [codecov-url]: https://app.codecov.io/gh/inspect-js/is-data-descriptor/
- [actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/inspect-js/is-data-descriptor
- [actions-url]: https://github.com/inspect-js/is-data-descriptor/actions
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