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Array creation types
(version: 0)
Benchmark.js
Comparing performance of:
Empty init vs Sized init
Created:
9 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var length = 1000
Tests:
Empty init
var array = []; for (var index = 0; index < length; index++){ array[index] = index; }
Sized init
var array = new Array(length); for (var index = 0; index < length; index++){ array[index] = index; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Empty init
Sized init
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36
Browser/OS:
Chrome 137 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=610073" width="100%" height="500px"></iframe>
Sized init
381K/s
Empty init
221K/s
View exact numbers
Test name
Executions per second
✓
Sized init
380,889 Ops/sec
Empty init
221,325 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down what is tested in this benchmark. The provided JSON represents two test cases: "Empty init" and "Sized init". These test cases are designed to measure the performance difference between creating an empty JavaScript array using two different approaches: 1. **Empty init**: In this approach, an empty array is created by simply initializing it as `var array = [];`. This method does not preallocate memory for the array. 2. **Sized init**: In this approach, a new array is created with a specified size using `var array = new Array(length);`. This method preallocates memory for the array. **Options being compared:** * Two approaches to create an empty JavaScript array * Performance difference between these two approaches **Pros and Cons of each approach:** 1. **Empty init ([])**: * Pros: + Memory-efficient, as it only allocates space for the array's metadata. + Can lead to better performance when working with small arrays or in memory-constrained environments. * Cons: + May require more JavaScript engine overhead to manage and extend the array. 2. **Sized init (new Array(length))**: * Pros: + Provides a clear and explicit size for the array, making it easier to reason about its behavior. + Can lead to better performance when working with large arrays or in scenarios where memory is not a concern. * Cons: + Allocates more memory upfront, which can be detrimental in memory-constrained environments. **Library/Functionality:** In this benchmark, no specific library or function is used. The test cases only rely on the built-in JavaScript array functionality. **Special JS feature/Syntax:** There are no special JavaScript features or syntaxes used in these test cases. They focus solely on comparing two approaches to create an empty array. Now, let's consider alternative approaches: * **Array constructor**: Another way to create an array is using the `Array()` constructor, like this: `var array = new Array(length)`. This approach is similar to the "Sized init" method but uses a different syntax. * **Typed arrays**: For performance-critical code or in scenarios where memory is not a concern, typed arrays (e.g., `Uint8Array`, `Int32Array`) can provide better performance than regular arrays. In summary, this benchmark measures the performance difference between creating an empty JavaScript array using two approaches: initializing it as an empty array (`[]`) and preallocating memory with `new Array(length)`.
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