Non-Index Keys

Return an array of an object's own enumerable property names which are not integer indices.

Usage

var nonIndexKeys = require( '@stdlib/utils/nonindex-keys' );

nonIndexKeys( obj )

Returns an array of an object's own enumerable property names which are not integer indices.

var arr = [ 1, 2, 3 ];
arr.a = 'foo';
arr.b = 'bar';

var keys = nonIndexKeys( arr );
// e.g., returns [ 'a', 'b' ]

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.
In contrast to the built-in Object.keys(), if provided null or undefined, the function returns an empty array, rather than throwing an error.

Examples

var nonIndexKeys = require( '@stdlib/utils/nonindex-keys' );

function Foo() {
    this[ 0 ] = 3.14;
    this.beep = 'boop';
    this.a = {
        'b': 'c'
    };
    return this;
}

Foo.prototype.foo = [ 'bar' ];

var obj = new Foo();
var keys = nonIndexKeys( obj );

console.log( keys );
// e.g., => [ 'beep', 'a' ]