Benchmark: Testing split vs lastindexOf

Script Preparation code:

var s1 = "ALX:PLY:THE:Piano";

Tests:

split and pop
var n1 = s1.split(":").pop();
lastindexof
var n1 = s1.substring(s1.lastIndexOf(":") + 1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
split and pop
lastindexof

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
split and pop	43511344.0 Ops/sec
lastindexof	74955224.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested, compared options, pros/cons, and other considerations.

**Benchmark Description**

The benchmark is designed to test two approaches for extracting the last part of a string in JavaScript: `split()` with `.pop()` and `lastIndexOf()` with `.substring()`. The input string is "ALX:PLY:THE:Piano".

**Options Compared**

Two options are being compared:

1. **Split and Pop**: This approach uses the `split()` method to split the string into an array of substrings at each colon (`:`), and then uses the `.pop()` method to get the last element of the array.
2. **LastIndexOf and Substring**: This approach uses the `lastIndexOf()` method to find the index of the last colon in the string, and then uses the `.substring()` method to extract the substring from that index to the end of the string.

**Pros/Cons**

Here are some pros and cons of each approach:

* **Split and Pop**:
	+ Pros: Simple and easy to understand. No need to handle edge cases like empty strings or null values.
	+ Cons: May be slower than `lastIndexOf()` due to the overhead of creating an array and poping from it. Also, may not work as expected if there are multiple consecutive colons in the string.
* **LastIndexOf and Substring**:
	+ Pros: Can be faster than `split()` and `.pop()`, especially for large strings. Also, can handle edge cases like empty strings or null values more robustly.
	+ Cons: Requires a deeper understanding of JavaScript indexing and may not be as intuitive as the `split()` approach.

**Library/Functionality**

In this benchmark, no external libraries are used beyond what's built into JavaScript. However, it's worth noting that if you're working with very large strings or need to optimize performance, you might consider using specialized libraries like ICU (International Components for Unicode) or others.

**Special JS Feature/Syntax**

This benchmark doesn't use any special JavaScript features or syntax that would require explanation beyond the `split()`, `.pop()`, `lastIndexOf()`, and `.substring()` methods. If you're familiar with these basics, you should be able to follow along.

**Other Considerations**

When optimizing performance in JavaScript, it's often useful to consider factors like:

* Cache efficiency: Are your operations caching results effectively?
* Overhead of function calls: Are your functions having an excessive number of overheads?
* Garbage collection: How is garbage collection impacting your program's performance?

Keep these considerations in mind when working on performance-critical JavaScript code.

**Alternatives**

Some alternative approaches to extract the last part of a string might include:

* Using `indexOf()` and `.substring()` instead of `lastIndexOf()`
* Using regular expressions to split the string
* Preprocessing the input string to simplify or optimize the extraction process

However, these alternatives would likely change the nature of the benchmark and may not be as straightforward to compare with the original approaches.

Related benchmarks:

Testing split vs lastindexOf (version: 0)

Testing split vs lastindexOf

Comparing performance of: split and pop vs lastindexof

Created: 5 years ago by: Guest

Jump to the latest result

split and pop

lastindexof

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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