Benchmark: lastIndexOf vs split

Script Preparation code:

var str = 'player/attack-bottom/1'

Tests:

lastIndexOf
const idx = str.lastIndexOf('/') const r1 = str.substring(0, idx) const r2 = str.substring(idx + 1, str.length)
split
const splited = str.split('/') const r1 = splited[0] const r2 = splited[splited.length - 1]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lastIndexOf
split

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/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
lastIndexOf	7211912.5 Ops/sec
split	18169176.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand what's being tested in this benchmark.

**Benchmark Overview**

The benchmark is designed to compare the performance of two approaches: `lastIndexOf` and `split`. The test is written in JavaScript, and it uses a sample string (`str`) that contains a single forward slash (`/`). The goal is to measure how fast these two methods can find the last occurrence of the slash or split the string into substrings using the slash as a delimiter.

**Options Compared**

The two options being compared are:

1. `lastIndexOf`: This method returns the index of the last occurrence of a substring in the string.
2. `split`: This method splits a string into an array of substrings using a specified delimiter (in this case, `/`).

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* `lastIndexOf`:
	+ Pros: Fast, efficient, and straightforward to use.
	+ Cons: May not be suitable for splitting strings into multiple substrings.
* `split`:
	+ Pros: Suitable for splitting strings into multiple substrings, can also be used for other types of string manipulation.
	+ Cons: Can be slower than `lastIndexOf` if only finding the last occurrence is needed.

**Library and Purpose**

In this benchmark, no external libraries are mentioned. However, it's worth noting that both `lastIndexOf` and `split` are built-in methods in JavaScript, so no additional dependencies are required.

**Special JS Feature or Syntax**

There doesn't appear to be any special JavaScript features or syntax being used in this benchmark. The code is straightforward and uses only basic JavaScript constructs.

**Other Alternatives**

If you needed to find the last occurrence of a substring or split a string into substrings, other alternatives might include:

* Using `String.prototype.lastIndexOf()` (same as `lastIndexOf`, but as a method call on the string object)
* Using a regular expression with the `g` flag at the end (e.g., `/\/$/`) to find the last occurrence of a pattern
* Using a library like Lodash or Ramda, which provide additional utility functions for string manipulation

In terms of splitting strings into multiple substrings, other alternatives might include:

* Using `String.prototype.split()` with an empty separator (e.g., `''`)
* Using a regular expression with the `g` flag at the end to split on multiple delimiters
* Using a library like Lodash or Ramda, which provide additional utility functions for string manipulation.

Related benchmarks:

lastIndexOf vs split (version: 0)

testing speed

Comparing performance of: lastIndexOf vs split

Created: 2 years ago by: Guest

Jump to the latest result

lastIndexOf

split

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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