Run results for: parse date

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36

Browser: Chrome 54

Operating system: Windows

Device Platform: Other

Date tested: 7 years ago

Test name	Executions per second
Regex	1762.7 Ops/sec
Substr	2275.1 Ops/sec

Script Preparation code:

var REGEX = /^(\d{4})-(\d{2})-(\d{2})(T(\d{2}):(\d{2})(:(\d{2}))?)?/;

function withRegex(str) {
	var match = str.match(REGEX);
	if (match) {
    	return new Date(parseInt(match[1]), parseInt(match[2]), parseInt(match[3]), parseInt(match[5]) || 0, parseInt(match[6]) || 0, parseInt(match[8]) || 0);
    }
	return null;
}

function withSubstr(str) {
  var year = parseInt(str.substr(0, 4), 10),
			month = parseInt(str.substr(5, 2), 10) - 1,
			day = parseInt(str.substr(8, 2), 10),
			hour = 0, minute = 0, second = 0;

		if (str.indexOf('T') > -1) {
			hour = parseInt(str.substr(11, 2), 10),
			minute = parseInt(str.substr(14, 2), 10),
			second = parseInt(str.substr(17, 2), 10);
		}

		return new Date(year, month, day, hour, minute, second);
}

Tests:

Regex
for (var i=0; i<100; ++i) { withRegex('1991-11-26T12:00:00'); withRegex('1991-11-26'); }
Substr
for (var i=0; i<100; ++i) { withSubstr('1991-11-26T12:00:00'); withSubstr('1991-11-26'); }