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[Array 10] flatMap vs reduce (concat) vs reduce (push)
(version: 0)
Comparing performance of:
Reduce concat vs FlatMap vs Reduce push
Created:
4 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var arr = Array(10).fill(1)
Tests:
Reduce concat
arr.reduce((acc, x, index) => acc.concat(x, index % 2 ? x : []), [])
FlatMap
arr.flatMap((x, index) => [x, index % 2 && x]).filter(Boolean)
Reduce push
arr.reduce((acc, x, index) => { acc.push(x); if(index % 2) { acc.push(x) } return acc; }, [])
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
Reduce concat
FlatMap
Reduce push
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 benchmark and explain what's being tested. **Benchmark Definition** The benchmark is comparing three different approaches to flatten an array of 10 elements: 1. `flatMap`: This method uses the spread operator (`...`) to create a new array with the result of applying a provided function on every element in the original array. 2. `reduce.concat`: This approach uses the `concat` method to concatenate arrays and reduce it to a single value. 3. `reduce.push`: This method uses the `push` method to add elements to an accumulator array. **Options Compared** The three options are being compared in terms of their performance, specifically: * Which one is faster? * Are there any significant differences in execution speed? **Pros and Cons of Each Approach:** 1. **flatMap**: This approach is concise and expressive. It's a modern JavaScript method that's designed for this kind of operation. However, it may incur some overhead due to the creation of a new array. 2. **reduce.concat**: This approach is simple and widely supported. It uses the `concat` method, which is a built-in method in JavaScript. However, it may be less efficient than `flatMap` since it creates multiple intermediate arrays. 3. **reduce.push**: This approach is also concise but uses the `push` method, which can be slower than using `concat`. Additionally, this approach requires an accumulator array to be initialized, which can lead to memory allocation issues. **Library Usage** None of the test cases use any external libraries. **Special JavaScript Features or Syntax** There are no special features or syntax used in these benchmark definitions. They're standard JavaScript methods and operators. **Other Considerations** * **Memory usage**: All three approaches have different memory usage implications. `flatMap` creates a new array, while `reduce.concat` creates multiple intermediate arrays, and `reduce.push` modifies an existing accumulator array. * **Cache locality**: The order of elements in the input array can affect performance. For example, if the array is sorted or has some pattern, it might improve cache locality for certain methods. **Alternatives** Other alternatives to flatten an array could include using a loop with an index variable: ```javascript arr.forEach((x, i) => { const flattenedArray = []; // ... }); ``` Or using `Array.prototype.map()` and then flattening the result with another method like `concat()` or `flat()`: ```javascript arr.map(x => x).concat(arr[0]).reduce((acc, x) => acc.concat(x), []); ``` However, these alternatives are likely to be slower than the three methods being compared in this benchmark.
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