Benchmark: startsWith vs include vs substring

Script Preparation code:

window.prefix = "%%SOME_PREFIX%%";
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

function makeRandomString(len) {
  var text = "";
  for( var i=0; i < len; i++ ) {
    text += possible.charAt(getRandomInt(possible.length));
  }
  return text;
}

window.allStrings = [];
for (let i = 0; i < 1000; i++) {
	allStrings.push(window.prefix + makeRandomString(1000));
	allStrings.push(makeRandomString(1000));
}

Tests:

JS startsWith
window.allStrings.forEach(s => { s.startsWith(window.prefix); })
JS includes
window.allStrings.forEach(s => { s.includes(window.prefix); })
JS substring
window.allStrings.forEach(s => { s.substring(0, window.prefix.length) === window.prefix; })

Historical Performance Data aggregated from 78 community runs

Desktop Results:

Chrome 59 runs

JS includes

6K/s

JS startsWith

5K/s

JS substring

3K/s

Fastest: JS includes (2.0x faster)

View exact numbers

✓ JS includes: 5,989 ops/sec
• JS startsWith: 4,986 ops/sec
• JS substring: 3,000 ops/sec

Firefox 14 runs

JS startsWith

4K/s

JS includes

4K/s

JS substring

2K/s

Fastest: JS startsWith (2.1x faster)

View exact numbers

✓ JS startsWith: 3,528 ops/sec
• JS includes: 3,514 ops/sec
• JS substring: 1,657 ops/sec

Safari 5 runs

JS startsWith

17K/s

JS substring

12K/s

JS includes

10K/s

Fastest: JS startsWith (1.8x faster)

View exact numbers

✓ JS startsWith: 17,490 ops/sec
• JS substring: 11,550 ops/sec
• JS includes: 9,602 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
JS startsWith
JS includes
JS substring

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36

Browser/OS: Chrome 149 on Windows

View result in a separate tab

JS substring

58K/s

JS includes

54K/s

JS startsWith

27K/s

View exact numbers

Test name	Executions per second
✓ JS substring	58,333 Ops/sec
JS includes	54,169 Ops/sec
JS startsWith	26,844 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.

**Benchmark Overview**

The benchmark compares the performance of three string operations: `startsWith`, `includes`, and `substring`. The script generates an array of 2000 random strings, which are used to test these operations. The benchmark is designed to measure the execution time of each operation on a large dataset.

**Options Compared**

1. **`startsWith`**: This method checks if a string starts with a given prefix.
2. **`includes`**: This method checks if a string contains a given substring.
3. **`substring`**: This method extracts a part of a string, starting from a specified index and with a specified length.

**Pros and Cons of Each Approach**

1. **`startsWith`**:
	* Pros: Fast, since it only needs to check the first character of the string against the prefix.
	* Cons: May not be suitable for large strings or prefixes, as it may cause unnecessary work.
2. **`includes`**:
	* Pros: Flexible and efficient, as it can search for any substring in the string.
	* Cons: May be slower than `startsWith` for small prefixes, since it needs to search through the entire string.
3. **`substring`**:
	* Pros: Efficient, since it only extracts a fixed-size part of the string.
	* Cons: May not be suitable for large strings or extracting long substrings.

**Library and Special JS Feature**

None of these operations use any libraries or special JavaScript features that are not widely supported. However, some modern browsers may optimize or implement these operations using more efficient algorithms.

**Other Considerations**

* The benchmark uses a random string generator to create the test data, which helps to eliminate bias towards specific strings.
* The script uses a fixed prefix and length for the generated strings, which simplifies the comparison between the three operations.
* The benchmark measures execution time per second (ExecutionsPerSecond), which provides a rough estimate of performance.

**Alternative Benchmarks**

To compare these operations, other benchmarks might focus on different aspects, such as:

1. **String similarity**: Measuring the similarity between two strings using metrics like Levenshtein distance or Jaro-Winkler distance.
2. **Regular expressions**: Comparing the performance of regular expression-based string matching (e.g., `RegExp.test()`).
3. **Hash-based lookup**: Using hash tables to store and look up strings, which can provide faster lookup times for certain use cases.

Keep in mind that different benchmarks may prioritize specific aspects of performance, such as raw execution speed or memory usage.

startsWith vs include vs substring (version: 0)

Comparing performance of: `JS startsWith vs JS includes vs JS substring`

Created: 5 years ago by: Guest

Go to the latest result

JS startsWith

JS includes

JS substring

Historical Performance Data aggregated from 78 community runs

Desktop Results:

Chrome 59 runs

Firefox 14 runs

Safari 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

startsWith vs include vs substring (version: 0)

Comparing performance of: JS startsWith vs JS includes vs JS substring

Created: 5 years ago by: Guest

Go to the latest result

JS startsWith

JS includes

JS substring

Historical Performance Data aggregated from 78 community runs

Desktop Results:

Chrome 59 runs

Firefox 14 runs

Safari 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `JS startsWith vs JS includes vs JS substring`