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RegExp constructor vs literal using exec
(version: 0)
Benchmark.js
Testing performance when using a new RegExp object vs a literal regex with exec method
Comparing performance of:
new RegExp() vs Literal
Created:
3 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var reConstructor = new RegExp('^[0-9a-fA-F]{24}$') var reLiteral = /^[0-9a-fA-F]{24}$/
Tests:
new RegExp()
reConstructor.exec('132abc67219f019afe12901a')
Literal
reLiteral.exec('132abc67219f019afe12901a')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
new RegExp()
Literal
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
11 months ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Edg/141.0.0.0
Browser/OS:
Chrome 141 on Mac OS X 10.15.7
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=619804" width="100%" height="500px"></iframe>
new RegExp()
16.8M/s
Literal
16.7M/s
View exact numbers
Test name
Executions per second
✓
new RegExp()
16,826,312 Ops/sec
Literal
16,741,214 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what's being tested. **Benchmark Overview** The benchmark compares the performance of two approaches: 1. **RegExp constructor**: Creating a new RegExp object using the `new` keyword. 2. **Literal regex with exec method**: Using a literal regex string and calling the `exec()` method on it. **Options Compared** The benchmark is comparing the execution speed of these two approaches when searching for a specific pattern in a given string. **Pros and Cons of Each Approach** 1. **RegExp constructor**: * Pros: Can be more flexible, as you can create complex regex patterns using the `pattern` and `flags` properties. * Cons: May lead to slower performance due to the overhead of creating a new RegExp object. 2. **Literal regex with exec method**: * Pros: Can be faster for simple cases, as it avoids the overhead of creating a new RegExp object. * Cons: Limited flexibility, as you're stuck with a fixed pattern. **Other Considerations** * The benchmark uses the `exec()` method, which can stop at the first match, potentially affecting performance. * The strings used in the test are 24 characters long, which is likely the maximum length of an Ethereum address (used for testing). **Library Used** None explicitly mentioned. However, RegExp objects use the ECMAScript Standard library. **Special JS Feature or Syntax** No special features or syntax are being tested in this benchmark. **Alternative Approaches** For similar benchmarks: * Using a regex engine like libregex or regex-js * Comparing other string searching methods, such as `indexOf()` or `includes()` * Testing performance with different regex flags (e.g., `g`, `i`, `m`) Keep in mind that benchmarking can be highly dependent on the specific test case and JavaScript environment. The results may vary depending on the execution context.
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