Calculate text dimensions of DOM element

Forked from good idea here: https://coderwall.com/p/kdi8ua - see discussion in comments.

Just playing around, but calculates either width or height of multiple elements:

• plugin on GitHub
• http://jsfiddle.net/drzaus/J2PhC/13/
• older version just font

Updated per "other styles" comment

// get width or height
!(function($) {
    var N = function(key) { return 'getTextSize.' + key; },
        fontMapping = function($o, font) {
            //return {"font": font.font || $o.css('font')};
            var result = {}; // don't affect original object
            $.each(font, function(prop, val) {
                result[prop] = (val || $o.css(prop));
            });
            return result;
        }
    ;

    $.fn.getTextSize = function(dimension, text, font) {
        dimension = (dimension || 'width');
        // figure out what font aspects we're concerned with
        if( typeof font === "string" ) {
            font = {"font": font};
        }
        // include other common style properties that affect sizing
        font = $.extend({"font": false, "text-transform": false, "letter-spacing": false}, font);

        // allow multiple calculations
        return $.map($(this), function(o) {
            var $o = $(o), $fake = $o.data(N('fake'));
            console.log($o, $fake);
            if (!$fake) {
                // cloning causes duplication issues on subsequent calls
                // can attach to parent, but may be unnecessary parsing vs. body if updating font each time
                $fake = $('<span>').hide().addClass('placeholder').empty().appendTo(document.body);
                $o.data(N('fake'), $fake);
            }
            return $fake.html(text || $o.val() || $o.text()).css(fontMapping($o, font))[dimension]();
        });    
    };
})(jQuery);

Usage:

$('.multiple-elements').getTextSize().join('px, ')+'px';
$('.single').getTextSize('height')[0];