is-data-descriptor

is-data-descriptor

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

Examples

true when the descriptor has valid properties with valid values. false when not an object or when the object has invalid properties.

var isDataDesc = require('is-data-descriptor'); var assert = require('assert'); assert.equal(true, isDataDesc({ value: 'foo' })); assert.equal(true, isDataDesc({ value: function () {} })); assert.equal(true, isDataDesc({ value: true })); assert.equal(false, isDataDesc('a')); assert.equal(false, isDataDesc(null)); assert.equal(false, isDataDesc([])); assert.equal(false, isDataDesc({ value: 'foo', bar: 'baz' })); assert.equal(false, isDataDesc({ value: 'foo', bar: 'baz' })); assert.equal(false, isDataDesc({ value: 'foo', get: function () {} })); assert.equal(false, isDataDesc({ get: function () {}, value: 'foo' }) ); assert.equal(false, isDataDesc({ value: 'foo', enumerable: 'foo' })); assert.equal(false, isDataDesc({ value: 'foo', configurable: 'foo' })); assert.equal(false, isDataDesc({ value: 'foo', writable: 'foo' }));

Valid properties

The only valid data descriptor properties are the following:

• configurable (required)
• enumerable (required)
• value (optional)
• writable (optional)

To be a valid data descriptor, either value or writable must be defined.

Invalid properties

A descriptor may have additional invalid properties (an error will not be thrown).

var foo = {}; Object.defineProperty(foo, 'bar', { enumerable: true, whatever: 'blah', // invalid, but doesn't cause an error get: function() { return 'baz'; } }); console.log(foo.bar); //=> 'baz'

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-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