You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
YZY eef3e25414
branch149
11 months ago
..
.github branch149 11 months ago
test branch149 11 months ago
.editorconfig branch149 11 months ago
.eslintrc branch149 11 months ago
.gitattributes branch149 11 months ago
.nycrc branch149 11 months ago
CHANGELOG.md branch149 11 months ago
LICENSE branch149 11 months ago
README.md branch149 11 months ago
index.js branch149 11 months ago
package.json branch149 11 months ago

README.md

is-descriptor Version Badge

github actions coverage License Downloads

npm badge

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);

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