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substr vs endsWith
(version: 0)
Measure the performance diff between substr with negative index and endsWith
Comparing performance of:
subStr vs endsWith
Created:
5 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var example = 'test the end';
Tests:
subStr
var endsWithEnd = example.substr(-3) === 'end'
endsWith
var endsWithEnd = example.endsWith('end');
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
subStr
endsWith
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the JavaScript microbenchmark on MeasureThat.net. **Benchmark Definition** The benchmark measures the performance difference between two string manipulation functions: `substr` with a negative index and `endsWith`. The `substr` function is used to extract a subset of characters from a string, while the `endsWith` function checks if a string ends with a specified suffix. **Options Compared** The benchmark compares the performance of two approaches: 1. **Negative Index in Substr**: This approach uses the negative index feature in JavaScript to start extracting characters from the end of the string. 2. **endsWith Function**: This approach uses the `endsWith` function, which is part of the String prototype in JavaScript. **Pros and Cons** * **Negative Index in Substr**: + Pros: Can be faster for short strings or when exact matching is required. + Cons: May lead to incorrect results if the negative index is not used carefully. Also, it requires a specific syntax that might not be widely supported by all JavaScript engines. * **endsWith Function**: + Pros: More concise and readable code, less prone to errors compared to using substr with negative indices. + Cons: Might be slower than the negative index approach for very large strings or when exact matching is required. **Other Considerations** The benchmark assumes that both functions are used on a specific string (`example = 'test the end';`). The test case uses the `===` operator to compare the extracted substring with the expected suffix, which is "end". It's worth noting that the negative index feature in JavaScript is available since ECMAScript 5 (ES5). If you're targeting older browsers or environments, this might not be an option. **Library and Purpose** The benchmark doesn't explicitly use a library, but it relies on the `String.prototype.endsWith` method, which is part of the ECMA-262 standard. The `endsWith` function is designed to provide a concise way to check if a string ends with a specified suffix. **Special JS Feature or Syntax** The negative index feature in JavaScript is a special syntax that allows you to start extracting characters from the end of a string. This feature is specific to ECMAScript 5 and later versions. If you're interested in exploring other alternatives, here are some options: 1. **Using a custom implementation**: You can write your own custom function for extracting substrings or checking if a string ends with a specified suffix. 2. **Other String manipulation functions**: Depending on the specific use case, you might consider using other string manipulation functions like `indexOf`, `lastIndexOf`, or regular expressions. 3. **Benchmarking frameworks**: MeasureThat.net uses a benchmarking framework to compare the performance of different approaches. There are other benchmarking frameworks available, such as Benchmark.js or jsperf, that can help you create and run JavaScript microbenchmarks. I hope this explanation helps you understand the context and nuances of the JavaScript microbenchmark on MeasureThat.net!
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