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flatMap vs reducedddd
(version: 0)
Comparing performance of:
reduce with concat vs flatMap
Created:
4 years ago
by:
Guest
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Script Preparation code:
var arr = Array(10_000).fill(0)
Tests:
reduce with concat
arr.reduce((acc, x) => { acc.push(x) return acc }, [])
flatMap
arr.flatMap(x => { return [x] })
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
reduce with concat
flatMap
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 benchmark and explain what's being tested. **Benchmark Definition** The benchmark measures the performance of two methods: `reduce` with concatenation (`acc.push(x)` inside the callback function) and `flatMap`. We'll dive into each test case separately. **Test Case 1: "reduce with concat"** * Benchmark Definition: `arr.reduce((acc, x) => { acc.push(x); return acc; }, [])` * Purpose: To measure the performance of pushing elements to an array using the `push` method and then returning the accumulator (`acc`) in each iteration. * Library/Functionality: The `reduce()` function is a built-in JavaScript Array method. It applies a user-provided callback function to each element in the array, accumulating the results. **Pros of using `reduce` with concatenation:** 1. Simplistic and straightforward approach. 2. Easy to understand and implement for developers familiar with array manipulation. **Cons of using `reduce` with concatenation:** 1. Creates a new array on each iteration by concatenating the existing elements, which can lead to inefficient memory allocation and deallocation. 2. Not optimized for performance in JavaScript engines. **Test Case 2: "flatMap"** * Benchmark Definition: `arr.flatMap(x => { return [x]; })` * Purpose: To measure the performance of flattening an array using the `flatMap()` function, which is a more modern replacement for the older `map().concat()` approach. **Pros of using `flatMap`:** 1. More memory-efficient than concatenating arrays. 2. Optimized by browsers and JavaScript engines for better performance. 3. Easier to read and understand than the older approach. **Cons of using `flatMap`:** 1. Introduced with ECMAScript 2019, making it less widely supported in older browsers or environments. **Other Considerations:** * Both test cases use a large array (`10_000`) filled with zeros for testing purposes. * The benchmark measures the number of executions per second (`ExecutionsPerSecond`), which indicates the performance difference between the two methods. **Alternatives:** 1. For `reduce`, consider using `forEach()` or other iteration methods if memory allocation concerns are not a priority. 2. If available, use modern JavaScript features like `Array.prototype.flatten()` (supporting ECMAScript 2019 and later) for even better performance. When using `flatMap()`, it's essential to note that it returns an array with the same length as the original array but without the overhead of concatenating arrays in each iteration. This makes it a more efficient choice for most modern JavaScript applications.
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