is-descriptor (1.0.3)
Installation
registry=npm install is-descriptor@1.0.3"is-descriptor": "1.0.3"About this package
is-descriptor 
Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.
Usage
const isDescriptor = require('is-descriptor');
const assert = require('assert');
assert.equal(isDescriptor({ value: 'foo' }), true);
assert.equal(isDescriptor({ get() {}, set() {} }), true);
assert.equal(isDescriptor({ get: 'foo', set() {} }), false);
You may also check for a descriptor by passing an object as the first argument and property name (string) as the second argument.
const obj = { foo: 'abc' };
Object.defineProperty(obj, 'bar', {
value: 'xyz'
});
assert.equal(isDescriptor(obj, 'foo'), true);
assert.equal(isDescriptor(obj, 'bar'), true);
Examples
value type
false when not an object
assert.equal(isDescriptor('a'), false);
assert.equal(isDescriptor(null), false);
assert.equal(isDescriptor([]), false);
data descriptor
true when the object has valid properties with valid values.
assert.equal(isDescriptor({ value: 'foo' }), true);
assert.equal(isDescriptor({ value() {} }), true);
false when the object has invalid properties
assert.equal(isDescriptor({ value: 'foo', enumerable: 'baz' }), false);
assert.equal(isDescriptor({ value: 'foo', configurable: 'baz' }), false);
assert.equal(isDescriptor({ value: 'foo', get() {} }), false);
assert.equal(isDescriptor({ get() {}, value() {} }), false);
false when a value is not the correct type
assert.equal(isDescriptor({ value: 'foo', enumerable: 'foo' }), false);
assert.equal(isDescriptor({ value: 'foo', configurable: 'foo' }), false);
assert.equal(isDescriptor({ value: 'foo', writable: 'foo' }), false);
accessor descriptor
true when the object has valid properties with valid values.
assert.equal(isDescriptor({ get() {}, set() {} }), true);
assert.equal(isDescriptor({ get() {} }), true);
assert.equal(isDescriptor({ set() {} }), true);
false when the object has invalid properties
assert.equal(isDescriptor({ get() {}, set() {}, enumerable: 'baz' }), false);
assert.equal(isDescriptor({ get() {}, writable: true }), false);
assert.equal(isDescriptor({ get() {}, value: true }), false);
false when an accessor is not a function
assert.equal(isDescriptor({ get() {}, set: 'baz' }), false);
assert.equal(isDescriptor({ get: 'foo', set() {} }), false);
assert.equal(isDescriptor({ get: 'foo', bar: 'baz' }), false);
assert.equal(isDescriptor({ get: 'foo', set: 'baz' }), false);
false when a value is not the correct type
assert.equal(isDescriptor({ get() {}, set() {}, enumerable: 'foo' }), false);
assert.equal(isDescriptor({ set() {}, configurable: 'foo' }), false);
assert.equal(isDescriptor({ get() {}, configurable: 'foo' }), false);
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.
- is-data-descriptor: Returns true if a value has the characteristics of a valid JavaScript data descriptor.
- 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
Dependencies
Dependencies
| ID | Version |
|---|---|
| is-accessor-descriptor | ^1.0.1 |
| is-data-descriptor | ^1.0.1 |
Development Dependencies
| ID | Version |
|---|---|
| @ljharb/eslint-config | ^21.1.0 |
| aud | ^2.0.3 |
| auto-changelog | ^2.4.0 |
| eslint | =8.8.0 |
| evalmd | ^0.0.19 |
| in-publish | ^2.0.1 |
| npmignore | ^0.3.0 |
| nyc | ^10.3.2 |
| safe-publish-latest | ^2.0.0 |
| tape | ^5.7.2 |