Benchmark: startswith vs set

Script Preparation code:

window.str = 'KELDIN_12345';
window.strSet = new Set(['WB',
    'ALZADA',
    'ASPEN',
    'EXPRESSO',
    'PACHECO',
    'KELDIN',
    'WINTERHAWK'
]);

Tests:

startswith
window.str.startsWith('WB') || window.str.startsWith('ALZADA') || window.str.startsWith('ASPEN') || window.str.startsWith('EXPRESSO') || window.str.startsWith('PACHECO') || window.str.startsWith('KELDIN') || window.str.startsWith('WINTERHAWK');
split
window.strSet.has(str.split('_')[0])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
startswith
split

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 provided benchmark and its test cases.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The goal of this benchmark is to compare the performance of two approaches: `startswith` and `set`.

The `startswith` approach checks if a string starts with a specific substring, while the `set` approach uses a Set data structure to store substrings and checks if a given string is present in the set.

**Script Preparation Code**

The script preparation code defines two variables:

* `window.str`: an empty string assigned to a global variable.
* `window.strSet`: a new Set object initialized with a list of substrings.

**Html Preparation Code**

There is no html preparation code provided, which means that this benchmark focuses solely on the JavaScript execution and does not take into account any HTML-related overhead.

**Individual Test Cases**

The benchmark consists of two test cases:

1. **startswith**
This test case uses the `startsWith` method to check if `window.str` starts with each of the substrings in the `strSet`. The benchmark definition is a logical OR operation between multiple `startsWith` calls.
2. **split**
This test case uses the `split()` method to split the `window.str` string into an array and then checks if the first element of the array (the substring before the underscore) is present in the `strSet`. The benchmark definition uses the `has()` method of the Set object.

**Pros and Cons**

Here's a brief analysis of each approach:

* **startswith**: This approach has a clear advantage when there are many substrings to check. However, it can be slower for shorter strings or fewer substrings, as it performs multiple checks.
	+ Pros: Simple to implement, works well with large datasets
	+ Cons: May be slower for short strings or fewer substrings
* **set**: This approach has a clear advantage when there are few substrings to check. However, it requires the use of a Set object, which can have overhead in terms of memory allocation and lookup.
	+ Pros: Faster for short strings or few substrings, uses less memory
	+ Cons: Requires the use of a Set object, may be slower for large datasets

**Libraries and Special JS Features**

In this benchmark, no libraries are used beyond the built-in JavaScript functions (`startsWith`, `split`, `Set`). No special JavaScript features like async/await or Promises are used either.

**Other Alternatives**

Some alternative approaches could include:

* Using a regular expression to match substrings instead of the `startsWith` method.
* Using a Trie data structure to store and search for substrings, which can be more efficient than Sets for large datasets.
* Implementing a custom lookup data structure using arrays or maps instead of Sets.

These alternatives would require changes to the benchmark code and might not provide significant performance benefits over the current approaches.

Related benchmarks:

startswith vs set (version: 0)

Comparing performance of: startswith vs split

Created: 2 years ago by: Guest

Jump to the latest result

startswith

split

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):