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.

Examples

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

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

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

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

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 when an accessor is not a function

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

false when a value is not the correct type

isAccessor({ get() {}, set() {}, enumerable: 'foo' });
isAccessor({ set() {}, configurable: 'foo' });
isAccessor({ get() {}, configurable: 'foo' });
//=> false

Related projects

You might also be interested in these projects:

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

Tests

Simply clone the repo, npm install, and run npm test

Changelog

v1.0.1 - 2023-10-26

Commits

• [eslint] actually use eslint a05c057
• [readme] clean up docs, URLs, package.json, etc 6648dcd
• [meta] update .gitignore cba0ea0
• [readme] remove verb 2f07da4
• [Tests] switch to tape 7e39202
• [Tests] migrate from travis to github actions aa436b0
• [Fix] properly handle an accessor descriptor with only a setter 04647f4
• [Refactor] properly guard for-in loop a0454cc
• [Fix] allow any non-primitive; arrays and functions are objects too 123e3c3
• [Refactor] use hasown 7ad36a0
• [readme] fix incorrect example 3ee754a
• [Tests] move tests to test dir 5d70880
• [Dev Deps] add missing npmignore 97ce4bc
• [Robustness] use a null object just in case 675af5b