is-accessor-descriptor

What is is-accessor-descriptor?

The is-accessor-descriptor npm package is used to check if an object property descriptor defines an accessor descriptor. An accessor descriptor is one that includes getter and/or setter functions, as opposed to a data descriptor which contains a value and is writable.

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

Check if a descriptor is an accessor descriptor

This feature allows you to verify if a given property descriptor from an object is an accessor descriptor. It returns true if the descriptor has a get or set key, and false otherwise.

{"isAccessorDescriptor": require('is-accessor-descriptor');
var descriptor = Object.getOwnPropertyDescriptor({get foo() {}}, 'foo');
console.log(isAccessorDescriptor(descriptor)); //=> true
}

Check if an object is an accessor descriptor

This feature allows you to check if a plain object mimics the structure of an accessor descriptor. It is useful for validation purposes when you have an object that should represent a descriptor and you want to ensure it is an accessor descriptor.

{"isAccessorDescriptor": require('is-accessor-descriptor');
console.log(isAccessorDescriptor({get: function() {}})); //=> true
console.log(isAccessorDescriptor({set: function() {}})); //=> true
console.log(isAccessorDescriptor({value: 123})); //=> false
}

Other packages similar to is-accessor-descriptor

is-data-descriptor

This package is similar to is-accessor-descriptor but checks for data descriptors instead. A data descriptor is an object with a value property and optionally writable, enumerable, and configurable properties. It is the counterpart to is-accessor-descriptor, which checks for accessor descriptors.

is-descriptor

is-descriptor is a more general package that checks if an object is a valid property descriptor, which can be either a data descriptor or an accessor descriptor. It is a superset of is-accessor-descriptor and is-data-descriptor functionalities.

is-plain-object

While not specifically for checking descriptors, is-plain-object can be used to determine if an object is plain (i.e., created by the Object constructor or one with a null prototype). This can be a preliminary check before further validation as a descriptor.

README

is-accessor-descriptor

Returns true if a value has the characteristics of a valid JavaScript accessor descriptor.

• Install
• Usage
• Examples
• API
• Related projects
• Running tests
• Contributing
• Author
• License

Install

Install with npm:

$ npm i is-accessor-descriptor --save

Usage

var isAccessor = require('is-accessor-descriptor');
var assert = require('assert');

assert.equal(isAccessor({ get() {} }), true);

You may also pass an object and property name to check if the property is an accessor:

assert.equal(isAccessor({ bar: 'foo' }, 'bar'), false);

Examples

false when not an object

assert.equal(isAccessor('a'), false);
assert.equal(isAccessor(null), false);

true when the object has valid properties

and the properties all have the correct JavaScript types:

assert.equal(isAccessor({ get() {}, set() {} }), true);
assert.equal(isAccessor({ get() {} }), true);
assert.equal(isAccessor({ set() {} }), true);

false when the object has invalid properties

assert.equal(isAccessor({ get() {}, set() {}, enumerable: 'baz' }), false);
assert.equal(isAccessor({ get() {}, writable: true }), false);
assert.equal(isAccessor({ get() {}, value: true }), false);
//=> false

false when an accessor is not a function

assert.equal(isAccessor({ get() {}, set: 'baz' }), false);
assert.equal(isAccessor({ get: 'foo', set() {} }), false);
assert.equal(isAccessor({ get: 'foo', bar: 'baz' }), false);
assert.equal(isAccessor({ get: 'foo', set: 'baz' }), false);
//=> false

false when a value is not the correct type

assert.equal(isAccessor({ get() {}, set() {}, enumerable: 'foo' }), false);
assert.equal(isAccessor({ set() {}, configurable: 'foo' }), false);
assert.equal(isAccessor({ get() {}, configurable: 'foo' }), false);
//=> 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
• is-descriptor: Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… more | homepage
• is-plain-object: Returns true if an object was created by the Object constructor. | 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.