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Reduce: Spread vs push
(version: 0)
Benchmark.js
Comparing performance of:
Spread vs Push
Created:
7 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var sut = [{ foo1: 'bar1' }, { foo2: 'bar2' }, { foo3: 'bar3' }];
Tests:
Spread
sut.reduce((acc, x) => [...acc, x], [])
Push
sut.reduce((acc, x) => { acc.push(x); return acc; }, [])
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
Spread
Push
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Linux; arm_64; Android 13; Air1 Ultra+) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.6834.122 YaBrowser/25.2.4.122.00 SA/3 Mobile Safari/537.36
Browser/OS:
Yandex Browser 25 on Android
View result in a separate tab
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=591566" width="100%" height="500px"></iframe>
Push
16.6M/s
Spread
4.4M/s
View exact numbers
Test name
Executions per second
✓
Push
16,585,179 Ops/sec
Spread
4,410,115 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to help you understand the JavaScript microbenchmark on MeasureThat.net. **Benchmark Overview** The benchmark is designed to compare two approaches for reducing an array in JavaScript: using the spread operator (`[...acc, x]`) versus pushing elements onto the accumulator array manually (`acc.push(x)`). **Benchmark Definition JSON** The benchmark definition JSON provides the following information: * **Name**: "Reduce: Spread vs push" * **Description**: None * **Script Preparation Code**: The script defines an object `sut` with three properties, which is used as the input for the reduction. * **Html Preparation Code**: None (meaning no HTML preparation is required) **Individual Test Cases** There are two test cases: 1. **Spread**: The benchmark definition uses the spread operator (`[...acc, x]`) to create a new array and concatenate it with the accumulator `acc`. This approach is expected to be faster since it avoids the overhead of pushing elements onto an array. 2. **Push**: The second benchmark definition manually pushes each element onto the accumulator array using the `push()` method. This approach can lead to slower performance since it involves more operations on the array. **Pros and Cons** * **Spread Operator (Test Case 1)**: + Pros: Efficiently creates a new array, avoids pushing elements onto an array. + Cons: Requires JavaScript version support for the spread operator (`[...acc, x]`). * **Push Operator (Test Case 2)**: + Pros: Works in older JavaScript versions that don't support the spread operator. + Cons: More operations are required on the array, potentially slower. **Library and Purpose** None of the test cases use any external libraries. The benchmark focuses solely on comparing two different reduction approaches. **Special JS Feature/Syntax** The `...` syntax used in the spread operator is a new feature introduced in ECMAScript 2015 (ES6). It allows for spreading an array or object into multiple arguments. **Other Alternatives** If you're interested in exploring other microbenchmarks, MeasureThat.net offers a wide range of tests covering various JavaScript-related topics. Some examples include: * Benchmarks on array manipulation operations like `sort()`, `filter()`, and `map()`. * Tests for string manipulation techniques like substring extraction and regular expression matching. * Comparisons of performance between different JavaScript engines (e.g., V8, SpiderMonkey) and browsers. Feel free to explore these alternatives if you're interested in learning more about JavaScript performance optimization!
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push vs spread (reduce array)
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