Benchmark: ISO Date parsing split vs slice

Script Preparation code:

var c = "2021-08-10T06:00:00.000Z"

Tests:

split
c.split('T')[0]
slice
c.slice(0, c.indexOf('T'))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
split
slice

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36

Browser/OS: Chrome 106 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
split	6479547.0 Ops/sec
slice	6821078.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches to parse out the date from an ISO string: using `split('T')` versus `slice(0, indexOf('T'))`. The goal is to determine which approach is faster.

**Library Used**

In this benchmark, a library called `indexOf()` is used. `indexOf()` is a method of strings that returns the index of the first occurrence of a specified value within the string. In this case, it's used to find the position of the 'T' character in the ISO string.

**Special JavaScript Feature/Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark.

**Approach Comparison**

The two approaches being compared are:

1. **`split('T')`**: This approach splits the ISO string into two parts using the `split()` method with a delimiter of 'T'. The resulting array contains two elements: the date part and the time part.
2. **`slice(0, indexOf('T'))`**: This approach uses the `indexOf()` method to find the position of the 'T' character in the ISO string and then uses the `slice()` method to extract a substring starting from the beginning of the string up to (but not including) the position of the 'T' character.

**Pros and Cons**

* **`split('T')`**:
	+ Pros: Simple and straightforward, easy to read.
	+ Cons: May have unnecessary overhead due to creating an array and iterating over its elements.
* **`slice(0, indexOf('T'))`**:
	+ Pros: Efficient, as it only extracts the substring up to the 'T' character without any unnecessary overhead.
	+ Cons: Requires using a method (`indexOf()`) that may not be supported by all browsers or environments.

**Other Considerations**

In this benchmark, the order of operations (the relative efficiency of `split()` vs. `slice()` with `indexOf()`) is what's being tested. The benchmark does not include any extra checks for proper formatting of the string or array size checking after the split, as specified in the Benchmark Definition.

**Alternatives**

Some alternative approaches could be:

* Using a regular expression to extract the date part and time part.
* Converting the ISO string to a JavaScript Date object using `new Date()` and then extracting the relevant parts (e.g., `date.getTime()`, `time.getHours()`, etc.).
* Using a library or function specifically designed for parsing ISO strings, such as Moment.js.

However, these alternatives are likely to introduce additional overhead and complexity compared to the simple string manipulation approaches being tested in this benchmark.

Related benchmarks:

ISO Date parsing split vs slice (version: 0)

Comparison of using split('T') or slice(0, indexOf('T')) in parsing out a date from an ISO string. Does not include any extra checking from the indexOf to ensure proper formatting of the string. Does not include array size checking after the split.

Comparing performance of: split vs slice

Created: 3 years ago by: Guest

Jump to the latest result

split

slice

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):