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padStart vs slice vs string
(version: 0)
Measures speed between using padStart and slice and string
Comparing performance of:
padStart vs splice vs string
Created:
2 years ago
by:
Guest
Go to the latest result
Tests:
padStart
let x = "5"; let res = x.padStart(2, "0")
splice
let x = "5"; let res = ("0" + x).slice(-2)
string
let x = 5; let res = x < 10 ? `0${x}` : `${x}`
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
padStart
splice
string
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36
Browser/OS:
Chrome 132 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=585474" width="100%" height="500px"></iframe>
string
106.7M/s
splice
101.8M/s
padStart
35.9M/s
View exact numbers
Test name
Executions per second
✓
string
106,650,968 Ops/sec
splice
101,823,456 Ops/sec
padStart
35,881,208 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the explanation of what is tested on the provided JSON. The benchmark measures the speed between three different approaches: 1. **`padStart()`**: This method pads the string with spaces on the left to reach a specified length. In this case, it's used to pad the string "5" with two zeros to make it at least 2 characters long. 2. **`slice()`**: This method extracts a section of a string and returns it as a new string. In this case, it's used to extract the last two characters of the concatenated string ("0" + x). 3. **String concatenation using template literals or implicit concatenation** (the `string` test case): This approach uses the fact that in JavaScript, you can concatenate strings by implicitly adding them together, like `"0" + x`. This is used to create a new string by prepending "0" to the value of x. Now, let's discuss the pros and cons of each approach: * **`padStart()`**: Pros: + It's a built-in method in JavaScript, so it's likely to be optimized for performance. + It's clear and concise way to pad a string. Cons: + May have additional processing overhead due to the padding process. + Can be slower than implicit concatenation or `slice()` for very large strings. * **`slice()`**: Pros: + Fast and efficient, as it only requires extracting a section of the string. + Can be faster than `padStart()` for very large strings. Cons: + Requires an additional function call, which can have overhead. + May not be as readable or concise as `padStart()`. * **String concatenation using template literals or implicit concatenation** (the `string` test case): Pros: + Fast and efficient, as it avoids the overhead of function calls and built-in methods. Cons: + May have additional complexity due to the use of implicit concatenation or template literals. + Can be less readable than other approaches. Other considerations: * The benchmark uses a relatively simple input string ("5") to test these approaches. For larger strings, `slice()` might still be faster, while `padStart()` could become slower due to its padding process. * The use of implicit concatenation or template literals can lead to additional complexity and potential issues if not handled correctly. Now, regarding the libraries used in these tests: None. These tests only rely on built-in JavaScript methods and features. As for special JS features or syntax, this benchmark doesn't explicitly test any specific features like async/await, promises, or ES6+ modules. However, it does use implicit concatenation, which is a more modern approach to string concatenation in JavaScript. Finally, other alternatives could include: * Using `repeat()` method instead of `padStart()`: This would create a new string with the specified number of repetitions of the pad character. * Using a custom function for padding or concatenation: Depending on the specific requirements and performance considerations, it might be beneficial to implement a custom solution using a loop or recursion. Keep in mind that these alternatives would likely have different trade-offs regarding performance, readability, and complexity.
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