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setting array length + assignation vs assignation vs push
(version: 0)
Benchmark.js
Comparing performance of:
Set length and assignation vs Push vs Assignation
Created:
3 years ago
by:
Guest
Go to the latest result
Tests:
Set length and assignation
var size = 100000; var arr2 = []; arr2.length = size; for (var i = 0; i < size; i++){ arr2[i] = i; }
Push
var size = 100000; var arr3 = []; for (var i = 0; i < size; i++){ arr3.push(i); }
Assignation
var size = 100000; var arr2 = []; for (var i = 0; i < size; i++){ arr2[i] = i; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
Set length and assignation
Push
Assignation
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
11 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36
Browser/OS:
Chrome 140 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=618912" width="100%" height="500px"></iframe>
Set length and assignation
7K/s
Push
2K/s
Assignation
2K/s
View exact numbers
Test name
Executions per second
✓
Set length and assignation
6,581 Ops/sec
Push
2,159 Ops/sec
Assignation
1,977 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Measuring the performance of different approaches to setting array length and assigning values in JavaScript is an interesting benchmark. **Benchmark Definition** The provided JSON defines three individual test cases: 1. **"Set length and assignation"**: This test case assigns a value to each index of the array using `arr2[i] = i;`. The array length is set using `arr2.length = size;`. 2. **"Push"**: This test case uses the `push()` method to add elements to the end of the array, without setting the initial length. 3. **"Assignation"**: This test case assigns a value to each index of the array without setting the initial length. **Options Compared** The benchmark compares three different approaches: 1. **Assigning values using indexing (`arr2[i] = i;`) and setting the length explicitly (`arr2.length = size;`)**: This approach is straightforward and easy to understand. 2. **Using `push()`**: The `push()` method adds elements to the end of the array without modifying the existing elements. This can be more efficient than assigning values using indexing for large arrays. 3. **Assigning values directly without setting the length (`arr[i] = i;`)**: This approach avoids setting the initial length, but it may lead to slower performance due to the overhead of dynamically resizing the array. **Pros and Cons** Here are some pros and cons of each approach: 1. **Assigning values using indexing and setting the length explicitly**: * Pros: Easy to understand, simple implementation. * Cons: May be slower for large arrays due to the overhead of setting the initial length. 2. **Using `push()`**: * Pros: Efficient for large arrays, avoids modifying existing elements. * Cons: May lead to slower performance if the array is dynamically resized frequently. 3. **Assigning values directly without setting the length**: * Pros: Avoids setting the initial length, potentially faster for small arrays. * Cons: May lead to slower performance due to dynamic resizing. **Libraries and Special Features** None of the test cases use any specific JavaScript library or feature that is not part of the standard language. **Other Alternatives** If you're interested in exploring alternative approaches, here are a few: 1. **Using `Array.prototype.set()`**: This method allows setting the length of an array and assigning values simultaneously. 2. **Using `Array.prototype.fill()`**: This method fills all elements of an array with a given value, which can be more efficient than using indexing. Keep in mind that these alternatives may have different performance characteristics or use cases compared to the approaches tested in this benchmark. Overall, the benchmark provides a useful comparison of three common approaches to setting array length and assigning values in JavaScript. The results highlight the importance of considering the specific requirements and constraints of your application when choosing an approach.
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