Simple method for returning object keys as an (optionally multidimensional) array, a la popular back-end languages. Uses the underlying Object.keys(obj) method where possible.

keyring.js

/**
 * Keyring - a quick polyfilled solution for getting object keys as an (optionally multidimensional) array.
 * 
 * Accepts an optional argument to recurse into and retrieve the keys of child objects as objects in the 
 * { obj: KEYNAME, keys: [KEYS] } format.
 * 
 * @author Steven Wiggins
 * @date 1/17/2014
 * @version 0.2.2
 **/
;(function(){

    Object.prototype.keyring = function( deep ) {
        
        var deep = ( typeof deep === 'boolean' ) ? deep : false,
            result = [],
            n = 0,
            key;
    
        if( Object.keys ) {
      
            result = Object.keys( this );
      
        } else {
      
            for( key in this ) {
        
                result.push( key );
        
            }
      
        }
        
        if( deep ) {
            
            n = result.length;
            
            while( n-- ) {
                
                key = result[ n ];
                
                if( typeof this[ key ] === 'object' ) {
                    
                    result[ n ] = {
                        obj  : key,
                        keys : this[ key ].keyring( true )
                    };
                    
                }
                
            }
            
        }
        
        return result;
    
    };

}());