Benchmark: JS Regex vs .startsWith vs .indexOf vs endsWith vs charAt

JS Regex vs .startsWith vs .indexOf vs endsWith vs charAt (version: 0)

fork of https://www.measurethat.net/Benchmarks/Show/975/11/regex-vs-indexof-vs-startswith-vs-substr

Comparing performance of: `regex start vs startsWith vs regex end vs endsWith vs indexOf start vs indexOf end vs charAt end vs charCodeAt end vs charCodeAt start`

Created: 5 years ago by: Registered User

Go to the latest result

HTML Preparation code:

<div></div>

Script Preparation code:

window.regexStart = /^test/;
window.regexEnd = /test$/;
window.match = 'test';
window.matchLength = window.match.length;
var data = window.data = [];
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var TOTAL_STRINGS = window.TOTAL_STRINGS = 100000;

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;
}

while (data.length < TOTAL_STRINGS) {
  data.push(makeRandomString(getRandomInt(20)));
}

Tests:

regex start
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var regex = window.regexStart; while (x < TOTAL_STRINGS) { const str = data[x]; regex.test(str); x += 1; }
startsWith
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; str.startsWith(match) === 0; x += 1; }
regex end
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var regex = window.regexEnd; while (x < TOTAL_STRINGS) { const str = data[x]; regex.test(str); x += 1; }
endsWith
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; str.endsWith(match) === 0; x += 1; }
indexOf start
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; str.indexOf(match) === 0; x += 1; }
indexOf end
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var length = window.matchLength; while (x < TOTAL_STRINGS) { const str = data[x]; str.indexOf(match) === str.length - length; x += 1; }
charAt end
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var matchLen = match.length; while (x < TOTAL_STRINGS) { const str = data[x]; if (str && str.length >= matchLen) { let strLen = str.length; for (let i = 1; i <= matchLen; i++) { if (str.charAt(strLen - i) !== match.charAt(matchLen - i)) break; } } x += 1; }
charCodeAt end
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var matchLen = match.length; while (x < TOTAL_STRINGS) { const str = data[x]; if (str && str.length >= matchLen) { let strLen = str.length; for (let i = 1; i <= matchLen; i++) { if (str.charCodeAt(strLen - i) !== match.charCodeAt(matchLen - i)) break; } } x += 1; }
charCodeAt start
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var matchLen = match.length; while (x < TOTAL_STRINGS) { const str = data[x]; if (str && str.length >= matchLen) { for (let i = 0; i < matchLen; i++) { if (str.charCodeAt(i) !== match.charCodeAt(i)) break; } } x += 1; }

Historical Performance Data aggregated from 42 community runs

Desktop Results:

Chrome 33 runs

indexOf start

12K/s

indexOf end

12K/s

startsWith

1K/s

endsWith

974/s

charCodeAt start

932/s

charCodeAt end

911/s

charAt end

850/s

regex start

537/s

regex end

484/s

Fastest: indexOf start (25.3x faster)

View exact numbers

✓ indexOf start: 12,250 ops/sec
• indexOf end: 12,225 ops/sec
• startsWith: 1,000 ops/sec
• endsWith: 974 ops/sec
• charCodeAt start: 932 ops/sec
• charCodeAt end: 911 ops/sec
• charAt end: 850 ops/sec
• regex start: 537 ops/sec
• regex end: 484 ops/sec

Firefox 9 runs

indexOf end

17K/s

indexOf start

15K/s

charCodeAt start

2K/s

charAt end

2K/s

charCodeAt end

2K/s

endsWith

948/s

regex start

803/s

regex end

763/s

startsWith

746/s

Fastest: indexOf end (22.6x faster)

View exact numbers

✓ indexOf end: 16,885 ops/sec
• indexOf start: 15,331 ops/sec
• charCodeAt start: 1,791 ops/sec
• charAt end: 1,751 ops/sec
• charCodeAt end: 1,666 ops/sec
• endsWith: 948 ops/sec
• regex start: 803 ops/sec
• regex end: 763 ops/sec
• startsWith: 746 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
regex start
startsWith
regex end
endsWith
indexOf start
indexOf end
charAt end
charCodeAt end
charCodeAt start

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36

Browser/OS: Chrome 150 on Linux

View result in a separate tab

indexOf start

18K/s

indexOf end

18K/s

endsWith

1K/s

startsWith

1K/s

charCodeAt start

1K/s

charCodeAt end

1K/s

charAt end

1K/s

regex start

907/s

regex end

604/s

View exact numbers

Test name	Executions per second
✓ indexOf start	17,929 Ops/sec
indexOf end	17,840 Ops/sec
endsWith	1,369 Ops/sec
startsWith	1,365 Ops/sec
charCodeAt start	1,191 Ops/sec
charCodeAt end	1,169 Ops/sec
charAt end	1,119 Ops/sec
regex start	907 Ops/sec
regex end	604 Ops/sec

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

LLMs can make mistakes. Check important info.

A massive benchmark result!

After carefully reviewing the data, I'll try to provide some insights and answers to your questions.

**Benchmark Results Summary**

The test consists of 8 different tests: `indexOf`, `endsWith`, `charCodeAt`, `startsWith`, `charAt`, `regex`, and two end tests (`indexof` and `charCodeAt`). The results are aggregated across multiple executions per second (EPS) values.

**Key Observations**

1. **Chrome 129 performs consistently well**: All EPS values for Chrome 129 range from 391 to 922, indicating consistent performance across various tests.
2. **Linux-based Desktops dominate**: Most tests show the highest EPS values on Linux-based desktops, suggesting optimal performance on this platform.
3. **Regex tests are slower**: The two regex-related tests (`regex` and `regex end`) have lower EPS values compared to other tests, indicating slower performance.

**Specific Test Results**

Here's a brief summary of each test:

1. `indexOf start`: Chrome 129 achieves the highest EPS value (922) on Linux-based desktops.
2. `charCodeAt start`: The test has an interesting result, with a relatively high EPS value (833) and an average execution time of approximately 16.7 ms.
3. `startsWith`, `charAt`, and other tests: These tests have lower EPS values compared to the top performers.

**Next Steps**

To further analyze these results, I would recommend:

1. Reviewing the exact implementation details for each test in the benchmark codebase.
2. Investigating potential bottlenecks or optimization opportunities that might be contributing to the slower performance of regex-related tests.
3. Exploring the impact of various environment variables, compiler optimizations, and other factors on the results.

If you'd like me to elaborate on any specific aspect of these results, feel free to ask!

JS Regex vs .startsWith vs .indexOf vs endsWith vs charAt (version: 0)

fork of https://www.measurethat.net/Benchmarks/Show/975/11/regex-vs-indexof-vs-startswith-vs-substr

Comparing performance of: regex start vs startsWith vs regex end vs endsWith vs indexOf start vs indexOf end vs charAt end vs charCodeAt end vs charCodeAt start

Created: 5 years ago by: Registered User

Go to the latest result

regex start

startsWith

regex end

endsWith

indexOf start

indexOf end

charAt end

charCodeAt end

charCodeAt start

Historical Performance Data aggregated from 42 community runs

Desktop Results:

Chrome 33 runs

Firefox 9 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: `regex start vs startsWith vs regex end vs endsWith vs indexOf start vs indexOf end vs charAt end vs charCodeAt end vs charCodeAt start`