Benchmark: parse date - MeasureThat.net

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'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
Substr

Fastest: N/A

Slowest: N/A

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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I'd be happy to explain what's tested in the provided JSON and describe the options compared.

**Benchmark Definition**

The benchmark definition is a JavaScript function that creates two regex patterns: `REGEX` and a string with `substr`. The functions, `withRegex` and `withSubstr`, take a string as input and attempt to parse it into a date using these patterns. If the parsing is successful, they return a new Date object; otherwise, they return null.

**Options Compared**

Two options are compared:

1. **Using regex**: The `withRegex` function uses a regular expression (regex) pattern to parse the date string. This approach involves:
	* Pros: More flexible and powerful than `substr` for parsing dates.
	* Cons: May be slower due to the complexity of regex patterns, especially for edge cases.
2. **Using substr**: The `withSubstr` function uses the `substr` method to extract specific parts from the date string before constructing a new Date object. This approach involves:
	* Pros: Faster and simpler than using regex, making it potentially more efficient.
	* Cons: Less flexible and less powerful than regex for parsing dates.

**Library Used**

There is no explicit library used in this benchmark definition. However, `substr` is a built-in JavaScript method that extracts a specified portion of the string.

**Special JS Feature or Syntax**

None are explicitly mentioned.

**Other Considerations**

When choosing between these two approaches, consider the trade-offs between flexibility, performance, and simplicity. If you need to handle edge cases or require precise date parsing, using regex might be a better choice. However, if you prioritize speed and can ensure that your input strings conform to specific formats, using `substr` could be faster.

**Alternatives**

If you were looking for alternative approaches, some options include:

1. **Using a dedicated date parsing library**, such as Moment.js or Luxon, which might provide better performance and features for date parsing.
2. **Using a string manipulation library**, like String.prototype.replace() or Intl.DateTimeFormat(), to extract specific parts of the date string before constructing a new Date object.

Keep in mind that these alternatives would require significant changes to your code and may introduce additional dependencies or complexity.

Related benchmarks:

parse date (version: 0)

Comparing performance of: Regex vs Substr

Created: 9 years ago by: Guest

Jump to the latest result

Regex

Substr

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):