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array from vs spread
(version: 0)
Comparing performance of:
array.from vs spread
Created:
7 years ago
by:
Guest
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Script Preparation code:
var arr = ['', '', ''];
Tests:
array.from
Array.from(arr)
spread
[...arr]
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
array.from
spread
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks! **What is being tested?** The provided JSON represents two test cases that compare the performance of creating an array using the `Array.from()` method versus the spread operator (`[...]`) with the same initial array. **Options compared:** 1. **`Array.from(arr)`**: This option uses the `Array.from()` method, which is a modern JavaScript method introduced in ECMAScript 2015 (ES6). It creates a new array by cloning and mapping over an existing iterable (in this case, the string array `arr`). The purpose of using `Array.from()` is to create a new array while preserving the original data. 2. **`[...arr]`**: This option uses the spread operator (`[...]`) to create a new array from the elements of the original array `arr`. The purpose of using the spread operator is to create a shallow copy of the array, which can be more efficient in some cases. **Pros and Cons:** * **`Array.from(arr)`**: + Pros: - Creates a new array that preserves the original data. - Can be more readable and maintainable for complex operations. + Cons: - May incur overhead due to the creation of an intermediate array (or a " cloned" version). - Might not be suitable for very large arrays, as it could lead to memory issues. * **`[...arr]`**: + Pros: - Creates a shallow copy of the array, which can be more efficient for small to medium-sized arrays. - More concise and readable syntax. + Cons: - Does not preserve the original data; instead, it creates a new array that references the same elements. - Can lead to unexpected behavior if modified after creation. **Library usage:** None of the provided test cases use any external libraries. The tests are focused solely on comparing the performance of the two approaches using built-in JavaScript methods. **Special JS feature or syntax:** There is no special feature or syntax mentioned in the provided code snippets, except for the spread operator (`[...]`), which is a relatively modern feature introduced in ECMAScript 2015 (ES6). **Other alternatives:** If you're looking for alternative approaches to create an array, consider using: 1. **`new Array(length)`**: Creates a new array with a specified length and initial value. 2. **`Array.prototype.fill()`**: Fills a new array with a specified value, starting from the beginning of the array. For example: ```javascript var arr = new Array(3); arr[0] = 'a'; arr[1] = 'b'; arr[2] = 'c'; // or var arr = []; for (var i = 0; i < 3; i++) { arr.push(i); } ``` Keep in mind that these alternatives may have different performance characteristics and trade-offs, depending on your specific use case. I hope this explanation helps you understand the provided benchmark test cases!
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