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js arr
(version: 0)
Comparing performance of:
new vs map vs for
Created:
6 years ago
by:
Guest
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Tests:
new
new Array(200).fill(200);
map
var x = 200, arr = Array.apply(null, Array(x)).map(x.valueOf, x);
for
var x = 200, arr = []; for (var i=0; i<x; i++) { arr.push(x); }
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Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
new
map
for
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 definitions and explain what's being tested, compared, and their pros and cons. **Benchmark Definitions** The benchmark definitions are in JavaScript, which is used to create an array of 200 elements and then perform operations on it. There are three test cases: 1. **"new"`**: Creates a new array using the `new` keyword. ```javascript new Array(200).fill(200); ``` This creates a new array with 200 elements, all initialized to the value 200. 2. **"map"`**: Uses the `Array.prototype.map()` method to create a new array. ```javascript var x = 200, arr = Array.apply(null, Array(x)).map(x.valueOf, x); ``` This creates a new array with the same number of elements as the original array, but each element is set to the value of `x` (200). 3. **"for"`**: Uses a traditional `for` loop to create an array. ```javascript var x = 200, arr = []; for (var i=0; i<x; i++) { arr.push(x); } ``` This creates a new array with the same number of elements as the original array, but each element is set to the value of `x` (200). **Comparison** The benchmark compares the performance of creating an array using these three different methods: `new`, `map`, and traditional `for` loop. **Pros and Cons** 1. **"new"`: * Pros: Simple, efficient, and widely supported. * Cons: Can be slower than other methods for large arrays. 2. **"map"`: * Pros: More concise and expressive, especially when working with higher-order functions. * Cons: Can be slower due to the overhead of the `map()` method and creating a new array. 3. **"for"`: * Pros: Control over indexing and iteration order. * Cons: Less concise and more verbose than other methods. **Library** None of these test cases use any external libraries or frameworks. **Special JS Features/Syntax** There are no special JavaScript features or syntax used in these benchmark definitions. They are straightforward and widely supported. **Other Alternatives** If you want to create an array with a certain number of elements, here are some alternative methods: * Using `Array.from()`: `Array.from({length: 200}, () => 200);` * Using `Array.fill()`: `new Array(200).fill(200)` * Using a generator function: `function* gen() { for (let i=0; i<200; i++) yield 200; } var arr = Array.from(gen());` Keep in mind that the performance of these alternatives may vary depending on the specific use case and browser.
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