Returns true if a value has the characteristics of a valid JavaScript data descriptor.
Install with npm:
sh
$ npm install --save is-data-descriptor
js
var isDataDesc = require('is-data-descriptor');
var assert = require('assert');
true when the descriptor has valid properties with valid values.
js
// `value` can be anything
assert.equal(isDataDesc({ value: 'foo' }), true);
assert.equal(isDataDesc({ value: function () {} }), true);
assert.equal(isDataDesc({ value: true }), true);
false when not an object
js
assert.equal(isDataDesc('a'), false);
assert.equal(isDataDesc(null), false);
false when the object has invalid properties
js
assert.equal(isDataDesc({ value: 'foo', enumerable: 'baz' }), false);
assert.equal(isDataDesc({ value: 'foo', configurable: 'baz' }), false);
assert.equal(isDataDesc({ value: 'foo', get() {} }), false);
assert.equal(isDataDesc({ get() {}, value: 'foo' }), false);
false when a value is not the correct type
js
assert.equal(isDataDesc({ value: 'foo', enumerable: 'foo' }), false);
assert.equal(isDataDesc({ value: 'foo', configurable: 'foo' }), false);
assert.equal(isDataDesc({ value: 'foo', writable: 'foo' }), false);
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).
```js 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'); ```
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