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Array constructor vs literal
(version: 0)
Comparing performance of:
Array constructor - 1000 items vs Array literal - 1000 items
Created:
9 years ago
by:
Guest
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Tests:
Array constructor - 1000 items
var n = 100000; var arr = new Array(n); for (var i = 0; i < n; i++) { arr[i] = i; }
Array literal - 1000 items
var n = 100000; var arr = []; for (var i = 0; i < n; i++) { arr.push(i); }
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Suite status:
<idle, ready to run>
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Test case name
Result
Array constructor - 1000 items
Array literal - 1000 items
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, compared, and other considerations. **Benchmark Definition** The benchmark is called "Array constructor vs literal". It measures the performance difference between creating an array using the `new Array` syntax versus creating an array directly with square brackets (`[]`). **Script Preparation Code** The script preparation code for this benchmark is empty. This means that the JavaScript engine has to create a new scope and variables every time the test runs. **Html Preparation Code** There is no html preparation code provided for this benchmark. **Individual Test Cases** There are two individual test cases: 1. "Array constructor - 1000 items" This test case creates an array using the `new Array` syntax and fills it with 1000 elements in a loop. 2. "Array literal - 1000 items" This test case creates an array directly with square brackets (`[]`) and fills it with 1000 elements in a loop. **Comparison** The two test cases are compared to determine which method is faster for creating large arrays. **Options Compared** The options being compared are: * `new Array` syntax * Directly creating an array with square brackets (`[]`) **Pros and Cons of Each Approach** 1. **`new Array` Syntax** * Pros: Can be used to create arrays with specific length, can be useful for array-based data structures. * Cons: May incur additional overhead due to the creation of a new object and prototype chain. 2. **Directly Creating an Array with Square Brackets (`[]`)** * Pros: Lightweight, fast, and flexible. * Cons: Does not provide explicit length information, may lead to unexpected behavior if not used carefully. **Library Used** There is no library explicitly mentioned in the benchmark definition or test cases. **Special JS Feature or Syntax** None of the provided test cases use any special JavaScript features or syntax. **Other Considerations** * The benchmark uses a loop to fill the array with elements, which can add overhead due to the repeated iterations. * The `for` loop used in both test cases may not be the most efficient choice for large arrays. Consider using more modern iterative methods like `Array.prototype.fill()` or `for...of`. * The benchmark is run on a Chrome browser version 53, which may have some performance characteristics different from newer versions. **Alternatives** If you want to explore alternative approaches, consider the following: * Use a library like `array-prototype-extensible` to create extensible arrays. * Experiment with other array creation methods, such as using `Set` or `Map`. * Use more modern JavaScript features like `Array.from()` or `Array.prototype.map()` to create arrays. Keep in mind that these alternatives may introduce new variables, dependencies, or performance characteristics, so be sure to thoroughly test and optimize your implementation.
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