UUID impl

guid.js

var Guid = (function() {

	/// Constructor:
	function Guid() {
		this.bytes = (function rec(acc, i) {
			return (0 > i || i > 31) ?
				acc :
				rec(acc.concat((Math.random() * 16 | 0).toString(16)), i + 1);
		})([], 0);
	}

	/// `Static` formats:
	Guid.formats = [
		"NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN",
		"NNNNNNNN-NNNN-NNNN-NNNN-NNNNNNNNNNNN",
		"{NNNNNNNN-NNNN-NNNN-NNNN-NNNNNNNNNNNN}",
		"(NNNNNNNN-NNNN-NNNN-NNNN-NNNNNNNNNNNN)",
		"{0xNNNNNNNN,0xNNNN,0xNNNN,{0xNN,0xNN,0xNN,0xNN,0xNN,0xNN,0xNN,0xNN}}",
	];
	
	Guid.empty = (function(){
		var g = new Guid();
		g.bytes = Guid.formats[0].replace(/N/g, "0").split("");
		return g;
	})();

	/// `Static` default format:
	Guid.defaultFormat = Guid.formats[1];
	
	Guid.prototype.toString = function Guid_toString(format) {
		var self = this;
		
		if (format === void 0 || format === null) {
			format = Guid.defaultFormat;
		} else {
			format = Guid.formats[format] || Guid.defaultFormat;
		}
		
		return (function() {
			var bs = self.bytes.slice(),
				maxi = format.length,
				result = [], i;
				
			if (format.split("N").length !== 33) {
				throw new Error("There has to be exactly 32 `N` in the format string.");
			}
				
			for (i = 0; i < maxi; i++) {
				if (format[i] === "N") {
					result.push(bs.shift());
				} else {
					result.push(format[i]);
				}
			}
			
			return result.join("");
		})();
	};
	
	Guid.prototype.valueOf = function Guid_valueOf() {
		return this.toString(0);
	};
	
	Guid.prototype.equals = function Guid_equals(other) {
		return this.valueOf() === other.valueOf();
	};
		
	return Guid;
})();

//var g = new Guid;
//console.log(g.toString(), g.toString(0), g.toString(1), g.toString(2), g.toString(3), g.toString(4));