Angle.js

/**
 * Wrapper for angle values; handles conversion to degrees from all allowed angle units
 * @constructor
 * @param {string} val The raw CSS value for the angle. It is assumed it has been pre-validated.
 */
PIE.Angle = (function() {
    function Angle( val ) {
        this.val = val;
    }
    Angle.prototype = {
        unitRE: /[a-z]+$/i,

        /**
         * @return {string} The unit of the angle value
         */
        getUnit: function() {
            return this._unit || ( this._unit = this.val.match( this.unitRE )[0].toLowerCase() );
        },

        /**
         * Get the numeric value of the angle in degrees.
         * @return {number} The degrees value
         */
        degrees: function() {
            var deg = this._deg, u, n;
            if( deg === undefined ) {
                u = this.getUnit();
                n = parseFloat( this.val, 10 );
                deg = this._deg = ( u === 'deg' ? n : u === 'rad' ? n / Math.PI * 180 : u === 'grad' ? n / 400 * 360 : u === 'turn' ? n * 360 : 0 );
            }
            return deg;
        }
    };

    return Angle;
})();