@stdlib/utils-writable-property-names NPM

writablePropertyNames

Return an array of an object's own writable property names.

Installation

npm install @stdlib/utils-writable-property-names

Usage

var writablePropertyNames = require( '@stdlib/utils-writable-property-names' );

writablePropertyNames( obj )

Returns an array of an object's own writable property names.

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' ]

Notes

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

Examples

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' ]

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.