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Pushing to an array vs copying and adding
(version: 0)
Comparing performance of:
Push vs Spread
Created:
6 years ago
by:
Guest
Jump to the latest result
HTML Preparation code:
<script src=''></script>
Script Preparation code:
var array = [] for(let i = 0; i < 1000; i++) { array.push(i) }
Tests:
Push
array.push(1001)
Spread
const n = [...array, 1001]
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
Push
Spread
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to explain the benchmark and its results. **Benchmark Overview** The provided JSON represents two microbenchmarks that test the performance of JavaScript arrays. The benchmarks are designed to measure the execution time of two different approaches: pushing an element onto an array using `array.push()` or copying and adding an element to an array using array destructuring (`const n = [...array, 1001]`). **Script Preparation Code** The script preparation code provided creates a large array with 1000 elements and pushes each element from 0 to 999 onto the array: ```javascript var array = []; for (let i = 0; i < 1000; i++) { array.push(i); } ``` This code sets up a test scenario where the focus is on the performance of `array.push()`. **Html Preparation Code** The html preparation code includes an empty `<script>` tag, which is likely used to load additional JavaScript libraries or scripts for future benchmarks. **Individual Test Cases** There are two individual test cases: 1. **Push**: Measures the execution time of `array.push(1001)`. 2. **Spread**: Measures the execution time of `const n = [...array, 1001]`. **Library Used (if any)** No specific libraries are mentioned in the provided JSON. **Special JS Feature/Syntax** The use of array destructuring (`const n = [...array, 1001]`) is a modern JavaScript feature introduced in ECMAScript 2015. This syntax allows for concise and expressive way to create new arrays by copying elements from an existing array. **Pros and Cons of Different Approaches** * **Push**: The classic approach to add elements to an array. Pros: widely supported, efficient in most browsers. Cons: may be slower due to the overhead of appending elements. * **Spread**: A modern approach that creates a new array by copying elements from the original array. Pros: concise, expressive syntax, and can be faster due to optimized implementations. Cons: requires support for modern JavaScript features, may be slower in older browsers. **Other Alternatives** If the benchmarks were to test other approaches, some alternatives could include: * Using `array.unshift()` or `array.splice()` instead of `push()` * Creating a new array using `Array.from(array)` or `Array.prototype.slice.call(array)` * Using `Set` data structures instead of arrays * Implementing custom array methods for performance optimizations **Additional Considerations** When interpreting the benchmark results, it's essential to consider factors such as: * Browser and device compatibility * Platform-specific optimization techniques * The size of the input data and its distribution * The frequency of usage and expected workloads In this specific case, the benchmark indicates that `array.push()` is faster than `const n = [...array, 1001]` in Chrome 78 on a Desktop with Mac OS X 10.13.5. However, it's crucial to consider these additional factors when drawing conclusions about performance and optimization strategies for real-world scenarios.
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Spread vs Push when copying array
Array slice vs for loop 1000 elements
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