GitHub - inspect-js/is-data-descriptor: Returns true if a value has the characteristics of a valid JavaScript data descriptor. (original) (raw)

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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:

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() { return 'baz'; } });

assert.equal(foo.bar, 'baz');

Tests

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