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JS array union large arrays - concat vs spread
(version: 0)
Comparing performance of:
Array concat vs Array spread vs Array concat - large numbers vs Array spread - large numbers
Created:
6 years ago
by:
Guest
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Tests:
Array concat
const a = ['a','b','c'] const b = [1,2,3,4] const c = a.concat(b)
Array spread
const a = ['a','b','c'] const b = [1,2,3,4] const c = [...a, ...b]
Array concat - large numbers
const a = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','x','y','z','w'] const b = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20] const c = a.concat(b)
Array spread - large numbers
const a = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','x','y','z','w'] const b = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20] const c = [...a,...b]
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Suite status:
<idle, ready to run>
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Test case name
Result
Array concat
Array spread
Array concat - large numbers
Array spread - large numbers
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Measuring JavaScript performance is a fascinating topic. **What is tested?** The provided JSON represents a benchmark test for comparing the performance of two ways to concatenate arrays in JavaScript: `concat()` and spread operator (`...`). The tests are designed to measure which approach is faster for both small and large arrays. **Options compared** There are two main options being compared: 1. **Array `concat()` method**: This method creates a new array by concatenating the elements of the original arrays. 2. **Spread operator (`...`)**: This operator creates a new array by spreading the elements of the original arrays. **Pros and Cons of each approach:** 1. **Array `concat()` method**: * Pros: + Well-established method, widely supported across browsers. + Can be used with other methods (e.g., `push()`, `splice()`) to manipulate arrays. * Cons: + Creates a new array, which can lead to performance issues for large datasets. + Can be slower than spread operator for very large arrays. 2. **Spread operator (`...`)**: * Pros: + More modern and efficient way of concatenating arrays. + Does not create a new array, reducing memory allocation and garbage collection overhead. * Cons: + Less widely supported across older browsers (pre-ES6). + May require additional setup or library support for older environments. **Library usage** None of the tests seem to use any external libraries. The `concat()` method is a built-in JavaScript function, and the spread operator is a native syntax introduced in ECMAScript 2015 (ES6). **Special JS features or syntax** The only notable feature used in this benchmark is the spread operator (`...`), which was introduced in ES6. This allows for more concise and efficient array concatenation. **Alternative approaches** Other alternatives to the `concat()` method include: 1. **`push()`**: Adding elements to an existing array using `push()`. 2. **`splice()`**: Modifying an array by adding or removing elements. 3. **`Array.prototype.reduce()`**: Using a reduction function to accumulate elements from two arrays. Each of these alternatives has its own trade-offs and performance characteristics, which may be worth exploring in the context of this benchmark or other performance-critical scenarios.
Related benchmarks:
simple spread vs concat benchmark
unshift vs spread vs concat
Concat vs Spread for Large Arrayss
spread vs concat vs unshift on 1000
spread vs concat vs unshift on 100000
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