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IS using regexes faster for string replace 2
(version: 1)
Comparing performance of:
replaceAll vs replace with global regex
Created:
11 months ago
by:
Guest
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HTML Preparation code:
<!--your preparation HTML code goes here-->
Script Preparation code:
let r = /[\[\]]/g
Tests:
replaceAll
"[this] [is] [a] [test]".replaceAll("[", "").replaceAll("]", "");
replace with global regex
"[this] [is] [a] [test]".replace(r, "");
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
replaceAll
replace with global regex
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
4 months ago
)
User agent:
Mozilla/5.0 (X11; Linux x86_64; rv:149.0) Gecko/20100101 Firefox/149.0
Browser/OS:
Firefox 149 on Linux
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=627029" width="100%" height="500px"></iframe>
replaceAll
4.9M/s
replace with global regex
3.2M/s
View exact numbers
Test name
Executions per second
✓
replaceAll
4,867,540 Ops/sec
replace with global regex
3,168,478 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated 11 months ago):
The benchmark in question evaluates the performance of different methods for replacing characters in a string using JavaScript. Specifically, it compares two approaches: one using the `String.prototype.replaceAll` method and the other using a regular expression with the `String.prototype.replace` method. ### Benchmark Overview 1. **Benchmark Cases:** - **replaceAll:** This method replaces all occurrences of a specified substring (in this case, the opening and closing brackets) with a new string. The test code is: ```javascript "[this] [is] [a] [test]".replaceAll("[", "").replaceAll("]", ""); ``` - **replace with global regex:** This approach uses a regular expression to match the brackets and replace them all at once. The test code is: ```javascript "[this] [is] [a] [test]".replace(r, ""); ``` Here, `r` is a global regular expression defined as `/[\\[\\]]/g`, which matches both the opening and closing brackets. ### Performance Results The benchmark results indicate the number of executions per second for both methods on a mobile device running Chrome Mobile: - **replace with global regex**: 1,791,908.625 executions/second - **replaceAll**: 800,972.625 executions/second ### Pros and Cons of Each Approach 1. **replaceAll:** - **Pros:** - Simplicity: The method is straightforward to use for replacing substrings. - Readability: Code is more readable compared to regular expressions for simple replacements. - **Cons:** - Performance: As shown in the benchmark results, it is slower than using a regex for this specific case, especially when handling multiple characters. - Limited to exact string matches. 2. **replace with global regex:** - **Pros:** - Performance: In this benchmark, replacing with a regex is significantly faster, suggesting it can handle multiple replacements more efficiently. - Flexibility: Regular expressions can accommodate a variety of patterns and complex matching criteria beyond simple string replacements. - **Cons:** - Complexity: Regular expressions can be difficult to understand and maintain, especially for developers less familiar with regex syntax. - May lead to unexpected results if not used properly (e.g., unintended matches). ### Considerations and Alternatives When choosing between these two methods for string replacement, developers need to consider both performance and code maintainability. Depending on the use case, developers may also consider: - **Using the `String.prototype.split` and `Array.prototype.join` methods**: For simple character replacement, some developers may prefer splitting the string on the target character(s) and then joining it back together with the desired character, although this approach may not always have the same performance characteristics as regex, especially with larger strings. - **Other String Manipulation Libraries**: There are libraries like Lodash that could provide utility functions for string manipulation, though they may come with additional overhead. Overall, the choice between `replaceAll` and regex depends on the specific needs of the application, particularly considering the trade-offs between speed and code clarity.
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