time-to-botec/squiggle/node_modules/@stdlib/utils/inherited-writable-property-symbols/README.md

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# inheritedWritablePropertySymbols

> Return an array of an object's inherited writable [symbol][@stdlib/symbol/ctor] properties.

<section class="usage">

## Usage

<!-- eslint-disable id-length -->

```javascript
var inheritedWritablePropertySymbols = require( '@stdlib/utils/inherited-writable-property-symbols' );
```

#### inheritedWritablePropertySymbols( obj\[, level] )

Returns an `array` of an object's inherited writable [symbol][@stdlib/symbol/ctor] properties.

<!-- eslint-disable id-length -->

```javascript
var defineProperty = require( '@stdlib/utils/define-property' );
var hasSymbolSupport = require( '@stdlib/assert/has-symbol-support' );
var Symbol = require( '@stdlib/symbol/ctor' );

var hasSymbols = hasSymbolSupport();
var symbols;
var f;

function Foo() {
    if ( hasSymbols ) {
        defineProperty( this, Symbol( 'a' ), {
            'configurable': false,
            'enumerable': false,
            'writable': true,
            'value': 'a'
        });
    }
    return this;
}

if ( hasSymbols ) {
    defineProperty( Foo.prototype, Symbol( 'b' ), {
        'configurable': false,
        'enumerable': false,
        'writable': true,
        'value': 'b'
    });
}

f = new Foo();
symbols = inheritedWritablePropertySymbols( f );
```

By default, the function walks an object's entire prototype chain. To limit the inheritance level, provide a `level` argument.

<!-- eslint-disable id-length -->

```javascript
var symbols = inheritedWritablePropertySymbols( [], 1 );
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   Property order is not guaranteed, as `object` property 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 properties, 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 hasSymbolSupport = require( '@stdlib/assert/has-symbol-support' );
var Symbol = require( '@stdlib/symbol/ctor' );
var inheritedWritablePropertySymbols = require( '@stdlib/utils/inherited-writable-property-symbols' );

var hasSymbols = hasSymbolSupport();
var symbols;
var obj;

function Foo() {
    this.a = 'a';
    defineProperty( this, 'b', {
        'configurable': false,
        'enumerable': false,
        'writable': false,
        'value': 'b'
    });
    if ( hasSymbols ) {
        this[ Symbol( 'a' ) ] = 'a';
        defineProperty( this, Symbol( 'b' ), {
            'configurable': false,
            'enumerable': false,
            'writable': false,
            'value': 'b'
        });
    }
    return this;
}

Foo.prototype.c = 'c';
defineProperty( Foo.prototype, 'd', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'd'
});
if ( hasSymbols ) {
    Foo.prototype[ Symbol( 'c' ) ] = 'c';
    defineProperty( Foo.prototype, Symbol( 'd' ), {
        'configurable': false,
        'enumerable': false,
        'writable': false,
        'value': 'd'
    });
}

obj = new Foo();
symbols = inheritedWritablePropertySymbols( obj );

console.log( symbols );
```

</section>

<!-- /.examples -->

<section class="links">

[ecma-262-for-in]: http://www.ecma-international.org/ecma-262/5.1/#sec-12.6.4

[@stdlib/symbol/ctor]: https://www.npmjs.com/package/@stdlib/symbol-ctor

</section>

<!-- /.links -->