RegExp creation

gistfile1.js

var REGEX = {
    NUMBER  : /^-?[0-9]*\.?[0-9]+$/,
    KEYWORD : /^(?:top\s+|bottom\s+)?(?:right|left)|(?:right\s+|left\s+)?(?:top|bottom)$/
};

var direction = RegExp([
    '^(?:',
        REGEX.NUMBER.source.slice(1, -1), 
        '|',
        '(?:', REGEX.KEYWORD.source.slice(1, -1), ')deg',
        '|', 
        0,
     ')$'].join(''));