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Compare Slice vs Splice
Comparing performance of:
Slice vs Splice
Created:
4 years ago
by:
Guest
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Script Preparation code:
var arr = Array(100000).fill(1); index = 50000;
Tests:
Slice
[...arr.slice(0, index), 'Item', ...arr.slice(index)]
Splice
[...arr].splice(index, 0, 'Item')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Slice
Splice
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON and explain what's being tested. **Benchmark Purpose** The benchmark is designed to compare two approaches for inserting an item at a specific index in an array: using `Array.prototype.slice()` and `Array.prototype.splice()`. The goal is to determine which approach is faster and more efficient. **Options Compared** There are two options being compared: 1. **Slice**: Using `arr.slice(0, index)` to create a new array with the first `index` elements, followed by concatenating `'Item'` and then the remaining elements using `[...arr.slice(index)]`. 2. **Splice**: Using `arr.splice(index, 0, 'Item')` to insert an item at the specified index. **Pros and Cons** * **Slice:** * Pros: * Creates a new array without modifying the original array. * Can be more predictable in terms of performance, as it avoids mutating the original array. * Cons: * Creates a new array, which can be memory-intensive for large datasets. * May incur additional overhead due to the creation and concatenation of arrays. * **Splice:** * Pros: * Modifies the original array in place, potentially reducing memory usage compared to slice. * Can be faster for large arrays, as it avoids creating a new array. * Cons: * Mutates the original array, which can lead to unexpected behavior or side effects. * May have performance variability depending on the browser's implementation and the size of the array. **Library Used** None. This benchmark is using native JavaScript methods: `Array.prototype.slice()` and `Array.prototype.splice()`, without any external libraries. **Special JS Feature/Syntax** The test case does not explicitly use any special JavaScript features or syntax beyond what's already described. However, it relies on the browser's implementation of these native methods to achieve the desired performance comparison. **Alternatives** If you were to rewrite this benchmark using a different approach, here are some alternatives: * Using `Array.prototype.concat()` instead of slice or splice: This would create a new array by concatenating two arrays, similar to how `splice` works. * Using an external library like Lodash's `insert` function: This would provide a more explicit and potentially more efficient way to insert an item at a specific index in an array. * Using a different data structure, such as a linked list or a tree data structure, which might offer better performance characteristics for this particular operation. Keep in mind that the choice of alternative depends on the specific requirements and constraints of your project.
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