Benchmark: String slice: full vs chunk

Script Preparation code:

var text = `Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer vitae molestie metus. Pellentesque sit amet sapien mi. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Aliquam finibus risus eros, sed luctus mauris cursus et. Praesent venenatis nisl quis rhoncus egestas. Aenean mi augue, auctor sollicitudin tellus et, imperdiet pharetra sem. Curabitur imperdiet vel turpis eget maximus. Nullam sed enim rutrum, placerat dolor ut, varius dui. Ut id pellentesque urna. Praesent at velit sem. Cras vel semper neque. Suspendisse potenti. Curabitur ligula sapien, ullamcorper id lacus nec, elementum interdum ligula. Proin lacinia dictum magna nec feugiat. In efficitur lobortis lectus sit amet consectetur. Pellentesque nec sapien pretium, semper ligula et, euismod risus.

Phasellus pharetra massa non hendrerit fermentum. Sed eu sodales massa. Nunc eu congue diam. Nulla rutrum commodo lobortis. Fusce tristique tempor placerat. Aliquam purus ex, feugiat non velit at, elementum vehicula lectus. Nam pellentesque est erat. Proin dapibus eleifend aliquam. Quisque in cursus augue, vel egestas augue. Mauris hendrerit condimentum rutrum. Praesent eleifend elit sit amet efficitur condimentum.

Maecenas lacinia convallis pretium. Aenean ut massa varius, rhoncus neque quis, imperdiet dui. Maecenas scelerisque massa enim, et cursus tortor dictum sed. Sed hendrerit justo non turpis tempus vehicula. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Praesent sit amet ultricies ligula, ut sollicitudin felis. Curabitur nec felis lacinia, facilisis lectus a, bibendum urna. Nunc et leo convallis, molestie velit in, aliquam nisl. Pellentesque ultrices dictum ullamcorper. Fusce lectus lectus, congue vitae ultrices mattis, porta ac erat. Cras dictum id sapien et vestibulum. Aliquam at metus eu turpis eleifend laoreet vel et dui. Mauris et ante accumsan, blandit metus a, sollicitudin neque. Pellentesque mollis sapien at neque pharetra bibendum. Vestibulum pharetra finibus nisi, vel ornare eros semper et. Curabitur fermentum leo eget quam blandit, non efficitur dolor vulputate.

Vestibulum dui lectus, feugiat ut dolor quis, scelerisque porta justo. Nullam sit amet accumsan nulla. Ut condimentum molestie mi a consequat. Nulla facilisi. Maecenas vulputate massa non condimentum tincidunt. Proin at nibh efficitur, elementum nulla ac, finibus mi. Donec non justo turpis. Duis vulputate venenatis pharetra. Maecenas dignissim, leo et ornare fringilla, eros nisi tempus massa, nec finibus ante nunc sit amet turpis. Curabitur et vulputate mauris. Fusce ultrices ex vitae magna suscipit, non venenatis sem porttitor. Mauris ac suscipit arcu. Maecenas suscipit iaculis nunc quis viverra. Fusce eget mi id lectus vestibulum semper. Phasellus ut tristique orci, quis aliquet neque. Quisque eu porttitor elit.

Morbi imperdiet ullamcorper tempus. Ut quis lectus pellentesque felis vestibulum pharetra. Ut urna magna, porta et velit at, rhoncus auctor metus. Sed interdum, lacus nec vestibulum dapibus, dolor leo tristique turpis, consectetur tincidunt justo tortor vel nunc. Maecenas imperdiet augue eu consequat tempor. Ut dapibus ex lorem, quis facilisis turpis dapibus eu. Sed sapien felis, tristique sit amet mauris rhoncus, aliquam blandit massa. Nam sed ultrices arcu. Curabitur ligula risus, commodo quis tempus a, viverra vitae justo. Etiam euismod leo ac massa tristique, at bibendum eros posuere.`;

Tests:

Slice full
for(let i = 0; i < 3400; i++) { const a = text.slice(i); }
Slice chunk
for(let i = 0; i < 3400; i++) { const a = text.slice(i, i + 34); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Slice full
Slice chunk

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
Slice full	3439.4 Ops/sec
Slice chunk	3559.1 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases, explaining what's being tested, compared options, pros and cons of those approaches, and other considerations.

**Benchmark Definition**

The benchmark is testing the performance of two different ways to slice a string in JavaScript:

1. `text.slice(i)` (full slice)
2. `text.slice(i, i + 34)` (chunked slice)

**What's being tested?**

Both tests are measuring the execution time of slicing a large string (`text`) using each approach.

**Options compared**

The two options being compared are:

1. **Full slice**: Using `text.slice(i)` to get a substring from index `i` to the end of the string.
2. **Chunked slice**: Using `text.slice(i, i + 34)` to get a substring of length 34 starting from index `i`.

**Pros and Cons**

* **Full slice (text.slice(i))**:
	+ Pros: Simple, straightforward approach. No need to worry about the chunk size.
	+ Cons: May result in slower performance due to unnecessary string creation and copying.
* **Chunked slice (text.slice(i, i + 34))**:
	+ Pros: Can be faster than full slice, as it avoids unnecessary string creation and copying. It also allows for more control over the chunk size.
	+ Cons: Requires specifying a fixed chunk size, which might not be optimal for all use cases.

**Other considerations**

* **String creation**: Both approaches create a new string object when slicing. However, the chunked slice approach may create fewer strings overall, as it avoids creating multiple substrings of varying lengths.
* **Browser behavior**: Different browsers might optimize or interpret these two approaches differently, affecting performance.

**Library usage**

The benchmark definition doesn't explicitly mention any libraries being used beyond standard JavaScript functionality. However, it's worth noting that some modern JavaScript engines and browsers may have optimized string slicing implementations that could affect the benchmark results.

**Special JS features or syntax**

This benchmark doesn't specifically test any special JS features or syntax. It only uses standard JavaScript syntax for slicing strings.

Now, regarding alternative approaches, here are a few:

* **Using `substring()` instead of `slice()`**: While similar to `slice()`, `substring()` is a separate method that might be optimized differently.
* **Using a regular expression**: Instead of slicing the string, using a regular expression to extract parts of the string could potentially be faster and more efficient.
* **Using an array or other data structure**: If the string is being used as part of larger data processing pipelines, using an array or other data structure might offer better performance.

Keep in mind that these alternative approaches would require significant changes to the benchmark definition and testing strategy.

Related benchmarks:

String slice: full vs chunk (version: 0)

Comparing performance of: Slice full vs Slice chunk

Created: 2 years ago by: Guest

Jump to the latest result

Slice full

Slice chunk

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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