dojo.validate.isValidDate = function()

in tapestry-framework/src/js/dojo-0.4.3-custom-4.1.6/dojo2.js.uncompressed.js [3128:3200]
59 lines of code
31 McCabe index (conditional complexity)

dojo.validate.isValidDate = function(dateValue, format) {
	dojo.deprecated("dojo.validate.datetime", "use dojo.date.parse instead", "0.5");
	// Default is the American format
	if (typeof format == "object" && typeof format.format == "string"){ format = format.format; }
	if (typeof format != "string") { format = "MM/DD/YYYY"; }

	// Create a literal regular expression based on format
	var reLiteral = format.replace(/([$^.*+?=!:|\/\\\(\)\[\]\{\}])/g, "\\$1");

	// Convert all the tokens to RE elements
	reLiteral = reLiteral.replace( "YYYY", "([0-9]{4})" );
	reLiteral = reLiteral.replace( "MM", "(0[1-9]|10|11|12)" );
	reLiteral = reLiteral.replace( "M", "([1-9]|10|11|12)" );
	reLiteral = reLiteral.replace( "DDD", "(00[1-9]|0[1-9][0-9]|[12][0-9][0-9]|3[0-5][0-9]|36[0-6])" );
	reLiteral = reLiteral.replace( "DD", "(0[1-9]|[12][0-9]|30|31)" );
	reLiteral = reLiteral.replace( "D", "([1-9]|[12][0-9]|30|31)" );
	reLiteral = reLiteral.replace( "ww", "(0[1-9]|[1-4][0-9]|5[0-3])" );
	reLiteral = reLiteral.replace( "d", "([1-7])" );

	// Anchor pattern to begining and end of string
	reLiteral = "^" + reLiteral + "$";

	// Dynamic RE that parses the original format given
	var re = new RegExp(reLiteral);
	
	// Test if date is in a valid format
	if (!re.test(dateValue))  return false;

	// Parse date to get elements and check if date is valid
	// Assume valid values for date elements not given.
	var year = 0, month = 1, date = 1, dayofyear = 1, week = 1, day = 1;

	// Capture tokens
	var tokens = format.match( /(YYYY|MM|M|DDD|DD|D|ww|d)/g );

	// Capture date values
	var values = re.exec(dateValue);

	// Match up tokens with date values
	for (var i = 0; i < tokens.length; i++) {
		switch (tokens[i]) {
		case "YYYY":
			year = Number(values[i+1]); break;
		case "M":
		case "MM":
			month = Number(values[i+1]); break;
		case "D":
		case "DD":
			date = Number(values[i+1]); break;
		case "DDD":
			dayofyear = Number(values[i+1]); break;
		case "ww":
			week = Number(values[i+1]); break;
		case "d":
			day = Number(values[i+1]); break;
		}
	}

	// Leap years are divisible by 4, but not by 100, unless by 400
	var leapyear = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));

	// 31st of a month with 30 days
	if (date == 31 && (month == 4 || month == 6 || month == 9 || month == 11)) return false; 

	// February 30th or 31st
	if (date >= 30 && month == 2) return false; 

	// February 29th outside a leap year
	if (date == 29 && month == 2 && !leapyear) return false; 
	if (dayofyear == 366 && !leapyear)  return false;

	return true;
}