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map vs forEach/push
(version: 0)
Comparing performance of:
map vs forEach/push
Created:
3 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
window.arr = new Array({ length: 100000 }, (_, i) => `Option ${i + 1}`);
Tests:
map
const newArr = window.arr.map(element => ({ label: element, value: element })); newArr.unshift({ label: 'User', value: 'User' });
forEach/push
const newArr = []; newArr.push({ label: 'User', value: 'User' }) window.arr.forEach(element => { newArr.push({ label: element, value: element }) })
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
map
forEach/push
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 provided JSON data and explain what's being tested in each test case. **Benchmark Definition** The benchmark is comparing two approaches to modify an array: using `Array.prototype.map()` with an arrow function, and using `Array.prototype.forEach()` with additional `push()` calls. **Script Preparation Code** This code creates a new array `window.arr` with 100,000 elements, each assigned a string value in the format "Option X", where X is the element index plus one. This array will be used as input for the benchmark tests. **Html Preparation Code** There is no HTML preparation code provided, which means that this benchmark only tests JavaScript performance and does not consider any DOM-related factors. **Test Cases** The test cases compare the execution time of two approaches: 1. **map**: The `Array.prototype.map()` method creates a new array with the results of applying an arrow function to each element in the original array. In this case, the arrow function transforms each element into an object with "label" and "value" properties. 2. **forEach/push**: This approach uses `Array.prototype.forEach()` to iterate over the elements in the original array, pushing new objects onto a separate array (`newArr`). After iterating over all elements, a single object is pushed onto the end of the `newArr` array. **Library and Special JS Features** There are no specific libraries used in these test cases. However, the use of arrow functions (e.g., `element => ({ label: element, value: element })`) is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). **Pros and Cons of Each Approach** 1. **map**: This approach has several advantages: * It creates a new array with the results, which can be more efficient than modifying the original array. * It uses a single iteration over the elements, which reduces the number of times the code is executed. * However, it also creates a new array, which can consume more memory. 2. **forEach/push**: This approach has some advantages: * It modifies the original array, which can be more efficient if the array needs to be modified later. * It uses less memory than creating a new array with `map()`. * However, it requires an additional iteration over the elements, which increases the number of times the code is executed. **Other Considerations** When choosing between these approaches, consider the specific use case and performance requirements: * If you need to process large datasets and don't care about modifying the original array, `map()` might be a better choice. * If you need to modify the original array or want to avoid creating a new array, `forEach/push` might be a better option. **Alternatives** If you're interested in exploring other approaches, here are some alternatives: 1. **filter() + slice()**: Create a new array using `Array.prototype.filter()` and then use `Array.prototype.slice()` to create a subset of the filtered array. 2. **reduce()**: Use `Array.prototype.reduce()` to accumulate the results into a single object or array. 3. **for...of loop**: Use a traditional `for` loop with an iterator to iterate over the elements. These alternatives can provide different trade-offs in terms of performance, memory usage, and code complexity.
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