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Regex JS testing
(version: 0)
Comparing performance of:
new Regex vs Regex vs Literal
Created:
5 years ago
by:
Guest
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Script Preparation code:
var reConstructor = new RegExp('^[0-9a-fA-F]{24}$') var reSimpleConstructor = RegExp('^[0-9a-fA-F]{24}$') var reLiteral = /^[0-9a-fA-F]{24}$/
Tests:
new Regex
reConstructor.test('132abc67219f019afe12901a')
Regex
reSimpleConstructor.test('132abc67219f019afe12901a')
Literal
reLiteral.test('132abc67219f019afe12901a')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
new Regex
Regex
Literal
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'll break down the benchmark for you. **Overview** The provided benchmark tests three ways of creating regular expressions in JavaScript: using `RegExp` constructor, a literal syntax, and a shorthand syntax (`new RegExp`). The test cases measure the performance difference between these approaches. **Benchmark Definition JSON** The benchmark definition JSON contains two parts: 1. **Script Preparation Code**: This section defines three regular expression constructors: * `reConstructor`: Creates a new regular expression object using the `RegExp` constructor. * `reSimpleConstructor`: Creates a shorthand regular expression object, equivalent to `new RegExp`. * `reLiteral`: Defines a literal regular expression pattern, which is used directly in the test cases. 2. **Html Preparation Code**: This section is empty, indicating that no HTML preparation is required. **Individual Test Cases** The benchmark defines three individual test cases: 1. `reConstructor.test('132abc67219f019afe12901a')`: Tests the performance of creating a regular expression using the `RegExp` constructor. 2. `reSimpleConstructor.test('132abc67219f019afe12901a')`: Tests the performance of shorthand syntax (`new RegExp`). 3. `reLiteral.test('132abc67219f019afe12901a')`: Tests the performance of literal syntax. **Performance Comparison** The benchmark measures the execution frequency (in executions per second) for each test case, which represents the performance difference between the three approaches: * `Regex` (using `new RegExp`) has a slightly higher execution frequency compared to `Literal`. * `Literal` is the fastest approach. * `new Regex` has a lower execution frequency compared to `Regex`. **Pros and Cons of Each Approach** 1. **`RegExp` constructor**: This approach provides more control over the regular expression's flags, options, and behavior. However, it may lead to slightly slower performance due to the overhead of creating an object. 2. **Shorthand syntax (`new RegExp`)**: This approach is concise and often used in practice, but it may have less control over the regular expression's behavior compared to the `RegExp` constructor. 3. **Literal syntax**: This approach provides a very concise way of defining regular expressions, with no performance overhead or object creation involved. However, it may not be as flexible or extensible as the other two approaches. **Library and Special Features** In this benchmark, there are no external libraries used. Additionally, there are no special JavaScript features (e.g., `async/await`, `promises`) mentioned in the code snippets. **Other Alternatives** If you need to compare performance of different regular expression engines or syntaxes, here are some alternatives: * `javascript-regexpr`: A benchmarking library specifically designed for comparing performance between different regular expression implementations. * `regex-benchmark`: Another benchmarking tool that allows comparing performance between various regular expression engines and syntaxes. * Creating a custom benchmark using your favorite JavaScript testing framework (e.g., Jest, Mocha) with a focus on regular expression performance comparisons.
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RegExp constructor vs literal vs RegExp+Literal
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RegExp constructor vs literal (re-do creation)
Test RegExp Performance
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