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spread vs while
(version: 0)
Comparing performance of:
spread vs while
Created:
6 years ago
by:
Guest
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Tests:
spread
var n = 100000; [...Array(n).keys()];
while
var n = 100000; var a = []; while(n--) { a[n] = n; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
spread
while
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON data for the JavaScript microbenchmark on MeasureThat.net. **What is tested:** The benchmark tests two approaches to create an array with 100,000 elements: 1. **Spread syntax**: The first test case uses the spread operator (`[...Array(n).keys()]`) to create an array of indices from 0 to `n-1`. This creates a new array and copies the indices into it. 2. **While loop**: The second test case uses a while loop (`var n = 100000; var a = []; while(n--) { a[n] = n; }`) to create an array of indices from 0 to `n-1`. This approach modifies the existing array `a` by assigning values to its elements in a loop. **Options compared:** The benchmark compares two approaches: * **Spread syntax**: Creates a new array with the specified number of elements, using the spread operator. * **While loop**: Modifies an existing array by assigning values to its elements in a loop. **Pros and cons:** * **Spread syntax**: + Pros: - Efficient in terms of memory allocation (only creates one new array). - Clear and concise syntax. + Cons: - Creates a new array, which may incur overhead due to memory allocation and copying. * **While loop**: + Pros: - Modifies an existing array, avoiding the need for memory allocation and copying. + Cons: - More verbose syntax. - May be slower due to the use of a loop and indexing. In general, the spread syntax is more concise and efficient when working with large arrays. However, the while loop can be beneficial in situations where the array needs to be modified in place, such as when working with large datasets that need to be processed incrementally. **Other considerations:** * **Performance:** The benchmark results show that the spread syntax outperforms the while loop approach. * **Memory usage:** The while loop approach uses more memory because it modifies an existing array, whereas the spread syntax creates a new array. * **Readability and maintainability:** The while loop approach can be harder to read and understand due to its verbose syntax. **Library and special JS features:** There are no libraries or special JavaScript features mentioned in this benchmark. **Alternative approaches:** Other alternatives for creating an array with 100,000 elements could include: * **Array.from() method:** This method creates a new array from an iterable (in this case, the range of indices from 0 to `n-1`). * **Looping over a range object:** This approach uses a loop to iterate over a range object (`Math.range(n)`), which provides a convenient way to generate arrays with a specified length. * **Using a library like Lodash:** Lodash provides utility functions, including ones for creating arrays from an array of indices. However, these alternatives are not compared in this benchmark.
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