sprintf utility function

sprintf.js

var sprintf = function (text) {
	var i = 1, args = arguments;
	return text.replace(/%(0)?(\d*)?\.?(\d*)?(s|f)/g, function (pattern) {
		var a = arguments,
			precision = +a[3],
			value = args[i++],
			padSize = +a[2] - (~~value).toString().length,
			padding = padSize > 0 ? (new Array(padSize + 1).join(a[1] || ' ')) : '';
		return padding + (a[4] === 'f' && a[3] ? value.toFixed(+precision) : value);
	});
};

console.log('[' + sprintf("%5.2f", Math.PI) + ']');
//[    3.14]
console.log('[' + sprintf("%.6f", Math.PI) + ']');
//[3.141593]
console.log('[' + sprintf("%5f", Math.PI) + ']');
//[    3.141592653589793]
console.log('[' + sprintf("%5.0f", Math.PI) + ']');
//[    3]
console.log('[' + sprintf("%5f", -Math.PI) + ']');
//[   -3.141592653589793]
console.log('[' + sprintf("%5f", 33.9) + ']');
//[   33.9]
console.log('[' + sprintf("%05f", 33.9) + ']');
//[00033.9]
console.log(sprintf('i got %f problems but %s aint one', 99, 'string formatting'));
//i got 99 problems but string formatting aint one