Benchmark: string split vs string substring 3

Script Preparation code:

var s1 = "foo|bar|test";

Tests:

Array.split
var n1 = s1.split('|'); console.log(n1.pop())
Substring
var pip = s1.lastIndexOf('|'); console.log(s1.substring(pip + 1));

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:

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

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

**Benchmark Definition**

The benchmark is testing two different approaches to perform a string manipulation operation:

1. **String Split**: Using the `split()` method to split a string into an array of substrings separated by a specified delimiter (`'|'`).
2. **Substring**: Using the `substring()` method to extract a part of a string starting from a specified index (`lastIndexOf('|')`).

**Options Compared**

The benchmark is comparing two options:

1. **Using `split()`**: This option uses the `split()` method to split the string into an array, and then accesses the last element using `pop()`.
2. **Using `substring()`**: This option uses the `lastIndexOf()` method to find the index of the last occurrence of the delimiter (`'|'`), and then extracts a part of the string starting from that index using `substring()`.

**Pros and Cons**

**Split()**

Pros:

* More intuitive and expressive, as it directly splits the string into an array.
* May be faster if the string is large and doesn't fit in memory as a single substring.

Cons:

* Creates an intermediate array, which can lead to increased memory usage and garbage collection overhead.
* Can be slower due to the overhead of creating the array and accessing its elements.

**Substring**

Pros:

* More efficient in terms of memory usage, as only a small part of the string is stored in memory.
* May be faster due to the optimized implementation of `substring()`.

Cons:

* Less intuitive and expressive, as it requires finding the index of the delimiter first.
* Can be slower if the string doesn't contain the delimiter or if the index is large.

**Library**

There is no library used in this benchmark. However, note that some JavaScript engines might provide additional optimization features or built-in methods for these operations (e.g., `String.prototype.split()` and `String.prototype.substring()`).

**Special JS Feature/Syntax**

None are explicitly mentioned in this benchmark. However, it's worth noting that the use of the `lastIndexOf()` method is a relatively modern JavaScript feature introduced in ECMAScript 2015.

**Other Alternatives**

In this specific case, there aren't many alternatives to these two approaches. Other options might include:

* Using regular expressions (e.g., `s1.match('|')`) for string splitting.
* Using the `indexOf()` method instead of `lastIndexOf()` for finding the index of a delimiter.

However, it's worth noting that these alternative methods might not be as efficient or expressive as the original two approaches.

Related benchmarks:

string split vs string substring 3 (version: 0)

Comparing performance of: Array.split vs Substring

Created: 5 years ago by: Guest

Jump to the latest result

Array.split

Substring

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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