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Define Regex inline vs not.
(version: 0)
Comparing performance of:
inline defined vs using one_regex
Created:
7 years ago
by:
Guest
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Script Preparation code:
ONE_REGEX = /^(?!.* $\s)[\w *()[\]'"/.&–-]+$/gm
Tests:
inline defined
(function (text) { const SOME_OTHER_REGEX = /^(?!.* $\s)[\w *()[\]'"/.&–-]+$/gm; SOME_OTHER_REGEX.test(text); })('bla')
using one_regex
(function (text) { ONE_REGEX.test(text); })('bla')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
inline defined
using one_regex
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark definition and test cases. **Benchmark Definition** The benchmark measures two approaches to defining regular expressions (regex) in JavaScript: 1. **Inline defined**: The regex is defined directly inside the function body, within the parentheses that contain the `test` method call. 2. **Using one_regex**: A separate variable, `ONE_REGEX`, is defined outside the function and used within the function. **Options Compared** The benchmark compares the performance of two approaches: * Inline definition of regex * Using a separate variable to define regex **Pros and Cons of Each Approach** 1. **Inline Definition** * Pros: + Can be more concise and easier to read, as the regex is defined directly where it's used. + Reduces the need for additional variables or memory allocation. * Cons: + May lead to larger function sizes due to the inline definition of the regex. + Can make debugging and maintenance more difficult, as the regex is deeply embedded in the code. 2. **Using one_regex** * Pros: + Separates the regex from the rest of the function body, making it easier to manage and maintain. + Can improve readability by explicitly defining the regex outside the function. * Cons: + Requires an additional variable declaration, which can increase memory usage. + May require more overhead due to the creation and storage of the regex object. **Library and Purpose** The `RegExp` class is used in both test cases. The `RegExp` constructor takes two arguments: a pattern string and an optional flags value. In this benchmark, the flags value is set to `'g'`, which enables global matching (i.e., matching all occurrences of the regex in the input string). **Special JS Feature/Syntax** None are mentioned or used explicitly in the provided test cases. **Other Alternatives** If you wanted to explore alternative approaches, consider these options: 1. **String.prototype.replace()**: Instead of using `RegExp.test()` directly, you could use `String.prototype.replace()` with a callback function that takes a match array as an argument. 2. **Use a library like Lodash's `regex` helper**: If you need to perform complex regex operations frequently, consider using a utility library like Lodash, which provides a range of regex helpers. **Benchmark Result** The benchmark results show the performance difference between the two approaches. The inline defined approach outperforms the "using one_regex" approach by a significant margin, likely due to the overhead of creating and storing the `ONE_REGEX` variable.
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