Benchmark: Array split vs string substring for dates

Script Preparation code:

var s = "2021-06-03T00:00:00.000Z";

Tests:

Array.split
var n = s.split("T")[0];
Substring
var n = s.substring(0, 10);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.split
Substring

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.164 Safari/537.36

Browser/OS: Chrome 91 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.split	6594958.5 Ops/sec
Substring	16607315.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**Benchmark Overview**

The provided benchmark is designed to compare the performance of two approaches for extracting a date from a string:

1. `Array.split`: Splits the input string using the substring `"T"` as the separator and takes the first element (index 0) of the resulting array.
2. `Substring`: Uses the `substring` method with a start index of 0 and a length of 10 to extract the date part from the original string.

**Options Compared**

In this benchmark, we have two options being compared:

* **Array.split**: This approach uses the `split` method followed by array indexing ( `[0]` ) to extract the desired substring.
* **Substring**: This approach directly uses the `substring` method with a specific start and length parameters.

**Pros and Cons**

### Array.split

Pros:

* Easy to read and understand, as it's a common pattern in JavaScript.
* Can be more flexible if you need to handle multiple separators or more complex splitting logic.

Cons:

* Creates an array object with at least two elements (the original string and the separator), which may incur some overhead due to array management.

### Substring

Pros:

* More efficient, as it directly extracts the desired substring without creating additional objects.
* Can be faster for large strings or performance-critical code.

Cons:

* May look less familiar or more confusing to some developers, especially those not using JavaScript extensively.
* Limited flexibility if you need to handle complex string manipulation or multiple separators.

**Library and Special JS Feature**

None of the test cases use any libraries. The only special feature mentioned is the use of a specific date format (`"2021-06-03T00:00:00.000Z"`), which is a widely used ISO 8601 standard for dates in JavaScript. This might affect the performance or parsing behavior of the benchmark, but it's not related to any specific library.

**Other Alternatives**

If you're looking for alternative approaches or want to explore other optimizations, here are some options:

* **Regex**: You could use a regular expression to extract the date part from the string. This might be more flexible than `Array.split` or `Substring`, but also potentially slower and more complex.
* **String manipulation libraries**: If you're dealing with very large strings or performance-critical code, you might consider using specialized string manipulation libraries like ICU (International Components for Unicode) or a custom implementation.

Keep in mind that these alternatives may have their own trade-offs in terms of readability, maintainability, and performance.

Related benchmarks:

Array split vs string substring for dates (version: 0)

Comparing performance of: Array.split vs Substring

Created: 3 years ago by: Guest

Jump to the latest result

Array.split

Substring

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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