is-descriptor

What is is-descriptor?

The is-descriptor npm package is used for checking if an object is a valid descriptor. Descriptors are objects that define the behavior of properties on JavaScript objects, such as whether they are writable, enumerable, or configurable, and they can also specify getter and setter functions. This package is useful for validation in libraries that manipulate object properties and descriptors, ensuring that operations like defining new properties or modifying existing ones are performed with valid descriptor objects.

What are is-descriptor's main functionalities?

Checking property descriptors

This feature allows you to check if a given object is a valid property descriptor. The code sample demonstrates checking various objects to see if they qualify as descriptors based on their properties.

const isDescriptor = require('is-descriptor');

console.log(isDescriptor({enumerable: false, configurable: true})); // true
console.log(isDescriptor({value: 'hello'})); // true
console.log(isDescriptor({get: function() {}})); // true
console.log(isDescriptor({set: undefined})); // false

Other packages similar to is-descriptor

is-data-descriptor

This package checks specifically for data descriptors, which are a type of property descriptor focusing on value properties rather than accessor properties (getters and setters). It's more specific compared to is-descriptor, which checks for both data and accessor descriptors.

is-accessor-descriptor

Similar to is-data-descriptor, this package focuses on checking for accessor descriptors, which define getter and setter functions for a property. It complements is-data-descriptor by covering the other main type of property descriptor, offering a more focused approach compared to the broader checks performed by is-descriptor.

README

is-descriptor

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 i is-descriptor --save

Usage

var isDescriptor = require('is-descriptor');

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

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

Related 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
• isobject: Returns true if the value is an object and not an array or null. | homepage

Running tests

Install dev dependencies:

$ npm i -d && npm test

Contributing

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

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright © 2015 Jon Schlinkert Released under the MIT license.

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This file was generated by verb-cli on October 04, 2015.