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forEach vs map, 100k!
(version: 0)
Comparing performance of:
forEach vs map
Created:
6 years ago
by:
Guest
Jump to the latest result
HTML Preparation code:
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
Tests:
forEach
const arr = _.range(0,100000) arr.forEach(x => arr[x] = x * 2) console.log(arr)
map
const arr = _.range(0,100000) const newArr = arr.map(x => x * 2) console.log(newArr)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
forEach
map
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 benchmark test case and explain what's being tested, compared, and other considerations. **Benchmark Overview** The benchmark is designed to compare the performance of two approaches: `forEach` and `map`. Both tests use the same input array size (100,000 elements) and are executed on a JavaScript engine. The goal is to determine which approach is faster for this specific use case. **Options Compared** Two options are compared: 1. **`forEach`**: This method iterates over an array using a callback function, where each element in the array is processed one by one. 2. **`map`**: This method also iterates over an array but returns a new array with the results of applying a provided function to every element in the original array. **Pros and Cons** Here are some pros and cons of each approach: * `forEach`: + Pros: Can be used when you need to perform side effects (e.g., modifying the original array) or when you can't return a value from the callback. + Cons: Iterates over the array sequentially, which can lead to slower performance compared to other methods. * `map`: + Pros: Returns a new array with transformed elements, making it easier to work with the result. Can be faster than `forEach` for larger arrays since it avoids modifying the original array. + Cons: Requires the creation of a new array, which can lead to increased memory usage. **Library and Syntax** In this benchmark, the `_` library (Lodash) is used to provide utility functions like `range()` and `map()`. The `map()` function is also compared directly without any additional libraries or syntax modifications. **Special JavaScript Feature/Syntax** None of the tests in this benchmark require any special JavaScript features or syntax beyond what's already discussed. They are straightforward, vanilla JavaScript implementations. **Alternative Approaches** Other approaches to iterating over arrays and transforming elements include: * `for` loop: An older approach that uses a manual index variable. * `reduce()`: A method that accumulates values in an array by applying a function to each element. * Other libraries or frameworks might provide optimized or specialized implementations for specific use cases. **Benchmark Preparation Code** The provided HTML preparation code includes the Lodash library, which is used to generate the initial input array (`_.range(0,100000)`). The script preparation code is empty in this case, indicating that no additional setup or configuration is required beyond what's already included in the HTML file.
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