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Return an array of an object's inherited writable symbol properties.

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stdlib-js/utils-inherited-writable-property-symbols

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inheritedWritablePropertySymbols

NPM version Build Status Coverage Status

Return an array of an object's inherited writable symbol properties.

Installation

npm install @stdlib/utils-inherited-writable-property-symbols

Alternatively,

  • To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
  • If you are using Deno, visit the deno branch (see README for usage intructions).
  • For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

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

inheritedWritablePropertySymbols( obj[, level] )

Returns an array of an object's inherited writable symbol properties.

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.

var symbols = inheritedWritablePropertySymbols( [], 1 );

Notes

  • Property order is not guaranteed, as object property enumeration is not specified according to the ECMAScript specification. In practice, however, most engines use insertion order to sort an object's properties, thus allowing for deterministic extraction.

Examples

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 );

See Also


Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

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License

See LICENSE.

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