122 lines
2.5 KiB
Markdown
122 lines
2.5 KiB
Markdown
<!--
|
|
|
|
@license Apache-2.0
|
|
|
|
Copyright (c) 2018 The Stdlib Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
|
|
-->
|
|
|
|
# writablePropertyNames
|
|
|
|
> Return an array of an object's own writable property names.
|
|
|
|
<section class="usage">
|
|
|
|
## Usage
|
|
|
|
<!-- eslint-disable id-length -->
|
|
|
|
```javascript
|
|
var writablePropertyNames = require( '@stdlib/utils/writable-property-names' );
|
|
```
|
|
|
|
#### writablePropertyNames( obj )
|
|
|
|
Returns an `array` of an object's own writable property names.
|
|
|
|
```javascript
|
|
var defineProperty = require( '@stdlib/utils/define-property' );
|
|
|
|
var obj = {
|
|
'a': 'b'
|
|
};
|
|
|
|
defineProperty( obj, 'c', {
|
|
'configurable': true,
|
|
'enumerable': true,
|
|
'writable': false,
|
|
'value': 'd'
|
|
});
|
|
|
|
var keys = writablePropertyNames( obj );
|
|
// returns [ 'a' ]
|
|
```
|
|
|
|
</section>
|
|
|
|
<!-- /.usage -->
|
|
|
|
<section class="notes">
|
|
|
|
## Notes
|
|
|
|
- Name order is not guaranteed, as `object` key enumeration is not specified according to the [ECMAScript specification][ecma-262-for-in]. In practice, however, most engines use insertion order to sort an `object`'s keys, thus allowing for deterministic extraction.
|
|
|
|
</section>
|
|
|
|
<!-- /.notes -->
|
|
|
|
<section class="examples">
|
|
|
|
## Examples
|
|
|
|
<!-- eslint-disable id-length -->
|
|
|
|
<!-- eslint no-undef: "error" -->
|
|
|
|
```javascript
|
|
var defineProperty = require( '@stdlib/utils/define-property' );
|
|
var writablePropertyNames = require( '@stdlib/utils/writable-property-names' );
|
|
|
|
function Foo() {
|
|
this.a = {
|
|
'b': 'c'
|
|
};
|
|
defineProperty( this, 'baz', {
|
|
'configurable': true,
|
|
'enumerable': true,
|
|
'writable': false,
|
|
'value': 'qux'
|
|
});
|
|
return this;
|
|
}
|
|
|
|
Foo.prototype.foo = [ 'bar' ];
|
|
defineProperty( Foo.prototype, 'bip', {
|
|
'configurable': false,
|
|
'enumerable': false,
|
|
'writable': false,
|
|
'value': 'bop'
|
|
});
|
|
|
|
var obj = new Foo();
|
|
var keys = writablePropertyNames( obj );
|
|
|
|
console.log( keys );
|
|
// => [ 'a' ]
|
|
```
|
|
|
|
</section>
|
|
|
|
<!-- /.examples -->
|
|
|
|
<section class="links">
|
|
|
|
[ecma-262-for-in]: http://www.ecma-international.org/ecma-262/5.1/#sec-12.6.4
|
|
|
|
</section>
|
|
|
|
<!-- /.links -->
|