1 |
3a515b92
|
cagy
|
# is-descriptor [](https://www.npmjs.com/package/is-descriptor) [](https://npmjs.org/package/is-descriptor) [](https://npmjs.org/package/is-descriptor) [](https://travis-ci.org/jonschlinkert/is-descriptor)
|
2 |
|
|
|
3 |
|
|
> Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.
|
4 |
|
|
|
5 |
|
|
## Install
|
6 |
|
|
|
7 |
|
|
Install with [npm](https://www.npmjs.com/):
|
8 |
|
|
|
9 |
|
|
```sh
|
10 |
|
|
$ npm install --save is-descriptor
|
11 |
|
|
```
|
12 |
|
|
|
13 |
|
|
## Usage
|
14 |
|
|
|
15 |
|
|
```js
|
16 |
|
|
var isDescriptor = require('is-descriptor');
|
17 |
|
|
|
18 |
|
|
isDescriptor({value: 'foo'})
|
19 |
|
|
//=> true
|
20 |
|
|
isDescriptor({get: function(){}, set: function(){}})
|
21 |
|
|
//=> true
|
22 |
|
|
isDescriptor({get: 'foo', set: function(){}})
|
23 |
|
|
//=> false
|
24 |
|
|
```
|
25 |
|
|
|
26 |
|
|
You may also check for a descriptor by passing an object as the first argument and property name (`string`) as the second argument.
|
27 |
|
|
|
28 |
|
|
```js
|
29 |
|
|
var obj = {};
|
30 |
|
|
obj.foo = 'abc';
|
31 |
|
|
|
32 |
|
|
Object.defineProperty(obj, 'bar', {
|
33 |
|
|
value: 'xyz'
|
34 |
|
|
});
|
35 |
|
|
|
36 |
|
|
isDescriptor(obj, 'foo');
|
37 |
|
|
//=> true
|
38 |
|
|
isDescriptor(obj, 'bar');
|
39 |
|
|
//=> true
|
40 |
|
|
```
|
41 |
|
|
|
42 |
|
|
## Examples
|
43 |
|
|
|
44 |
|
|
### value type
|
45 |
|
|
|
46 |
|
|
`false` when not an object
|
47 |
|
|
|
48 |
|
|
```js
|
49 |
|
|
isDescriptor('a');
|
50 |
|
|
//=> false
|
51 |
|
|
isDescriptor(null);
|
52 |
|
|
//=> false
|
53 |
|
|
isDescriptor([]);
|
54 |
|
|
//=> false
|
55 |
|
|
```
|
56 |
|
|
|
57 |
|
|
### data descriptor
|
58 |
|
|
|
59 |
|
|
`true` when the object has valid properties with valid values.
|
60 |
|
|
|
61 |
|
|
```js
|
62 |
|
|
isDescriptor({value: 'foo'});
|
63 |
|
|
//=> true
|
64 |
|
|
isDescriptor({value: noop});
|
65 |
|
|
//=> true
|
66 |
|
|
```
|
67 |
|
|
|
68 |
|
|
`false` when the object has invalid properties
|
69 |
|
|
|
70 |
|
|
```js
|
71 |
|
|
isDescriptor({value: 'foo', bar: 'baz'});
|
72 |
|
|
//=> false
|
73 |
|
|
isDescriptor({value: 'foo', bar: 'baz'});
|
74 |
|
|
//=> false
|
75 |
|
|
isDescriptor({value: 'foo', get: noop});
|
76 |
|
|
//=> false
|
77 |
|
|
isDescriptor({get: noop, value: noop});
|
78 |
|
|
//=> false
|
79 |
|
|
```
|
80 |
|
|
|
81 |
|
|
`false` when a value is not the correct type
|
82 |
|
|
|
83 |
|
|
```js
|
84 |
|
|
isDescriptor({value: 'foo', enumerable: 'foo'});
|
85 |
|
|
//=> false
|
86 |
|
|
isDescriptor({value: 'foo', configurable: 'foo'});
|
87 |
|
|
//=> false
|
88 |
|
|
isDescriptor({value: 'foo', writable: 'foo'});
|
89 |
|
|
//=> false
|
90 |
|
|
```
|
91 |
|
|
|
92 |
|
|
### accessor descriptor
|
93 |
|
|
|
94 |
|
|
`true` when the object has valid properties with valid values.
|
95 |
|
|
|
96 |
|
|
```js
|
97 |
|
|
isDescriptor({get: noop, set: noop});
|
98 |
|
|
//=> true
|
99 |
|
|
isDescriptor({get: noop});
|
100 |
|
|
//=> true
|
101 |
|
|
isDescriptor({set: noop});
|
102 |
|
|
//=> true
|
103 |
|
|
```
|
104 |
|
|
|
105 |
|
|
`false` when the object has invalid properties
|
106 |
|
|
|
107 |
|
|
```js
|
108 |
|
|
isDescriptor({get: noop, set: noop, bar: 'baz'});
|
109 |
|
|
//=> false
|
110 |
|
|
isDescriptor({get: noop, writable: true});
|
111 |
|
|
//=> false
|
112 |
|
|
isDescriptor({get: noop, value: true});
|
113 |
|
|
//=> false
|
114 |
|
|
```
|
115 |
|
|
|
116 |
|
|
`false` when an accessor is not a function
|
117 |
|
|
|
118 |
|
|
```js
|
119 |
|
|
isDescriptor({get: noop, set: 'baz'});
|
120 |
|
|
//=> false
|
121 |
|
|
isDescriptor({get: 'foo', set: noop});
|
122 |
|
|
//=> false
|
123 |
|
|
isDescriptor({get: 'foo', bar: 'baz'});
|
124 |
|
|
//=> false
|
125 |
|
|
isDescriptor({get: 'foo', set: 'baz'});
|
126 |
|
|
//=> false
|
127 |
|
|
```
|
128 |
|
|
|
129 |
|
|
`false` when a value is not the correct type
|
130 |
|
|
|
131 |
|
|
```js
|
132 |
|
|
isDescriptor({get: noop, set: noop, enumerable: 'foo'});
|
133 |
|
|
//=> false
|
134 |
|
|
isDescriptor({set: noop, configurable: 'foo'});
|
135 |
|
|
//=> false
|
136 |
|
|
isDescriptor({get: noop, configurable: 'foo'});
|
137 |
|
|
//=> false
|
138 |
|
|
```
|
139 |
|
|
|
140 |
|
|
## About
|
141 |
|
|
|
142 |
|
|
### Related projects
|
143 |
|
|
|
144 |
|
|
* [is-accessor-descriptor](https://www.npmjs.com/package/is-accessor-descriptor): Returns true if a value has the characteristics of a valid JavaScript accessor descriptor. | [homepage](https://github.com/jonschlinkert/is-accessor-descriptor "Returns true if a value has the characteristics of a valid JavaScript accessor descriptor.")
|
145 |
|
|
* [is-data-descriptor](https://www.npmjs.com/package/is-data-descriptor): Returns true if a value has the characteristics of a valid JavaScript data descriptor. | [homepage](https://github.com/jonschlinkert/is-data-descriptor "Returns true if a value has the characteristics of a valid JavaScript data descriptor.")
|
146 |
|
|
* [is-descriptor](https://www.npmjs.com/package/is-descriptor): Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for… [more](https://github.com/jonschlinkert/is-descriptor) | [homepage](https://github.com/jonschlinkert/is-descriptor "Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.")
|
147 |
|
|
* [isobject](https://www.npmjs.com/package/isobject): Returns true if the value is an object and not an array or null. | [homepage](https://github.com/jonschlinkert/isobject "Returns true if the value is an object and not an array or null.")
|
148 |
|
|
|
149 |
|
|
### Contributing
|
150 |
|
|
|
151 |
|
|
Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
|
152 |
|
|
|
153 |
|
|
### Contributors
|
154 |
|
|
|
155 |
|
|
| **Commits** | **Contributor** |
|
156 |
|
|
| --- | --- |
|
157 |
|
|
| 24 | [jonschlinkert](https://github.com/jonschlinkert) |
|
158 |
|
|
| 1 | [doowb](https://github.com/doowb) |
|
159 |
|
|
| 1 | [wtgtybhertgeghgtwtg](https://github.com/wtgtybhertgeghgtwtg) |
|
160 |
|
|
|
161 |
|
|
### Building docs
|
162 |
|
|
|
163 |
|
|
_(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_
|
164 |
|
|
|
165 |
|
|
To generate the readme, run the following command:
|
166 |
|
|
|
167 |
|
|
```sh
|
168 |
|
|
$ npm install -g verbose/verb#dev verb-generate-readme && verb
|
169 |
|
|
```
|
170 |
|
|
|
171 |
|
|
### Running tests
|
172 |
|
|
|
173 |
|
|
Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:
|
174 |
|
|
|
175 |
|
|
```sh
|
176 |
|
|
$ npm install && npm test
|
177 |
|
|
```
|
178 |
|
|
|
179 |
|
|
### Author
|
180 |
|
|
|
181 |
|
|
**Jon Schlinkert**
|
182 |
|
|
|
183 |
|
|
* [github/jonschlinkert](https://github.com/jonschlinkert)
|
184 |
|
|
* [twitter/jonschlinkert](https://twitter.com/jonschlinkert)
|
185 |
|
|
|
186 |
|
|
### License
|
187 |
|
|
|
188 |
|
|
Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert).
|
189 |
|
|
Released under the [MIT License](LICENSE).
|
190 |
|
|
|
191 |
|
|
***
|
192 |
|
|
|
193 |
|
|
_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on July 22, 2017._
|