Toggle navigation
MeasureThat.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
Array constructor vs literal performance, corrected
(version: 0)
Comparing performance of:
Array constructor - 10 items vs Array literal (assign by index) - 10 items
Created:
5 years ago
by:
Guest
Jump to the latest result
Tests:
Array constructor - 10 items
var n = 10; var arr = new Array(); for (var i = 0; i < n; i++) { arr.push(i); }
Array literal (assign by index) - 10 items
var n = 10; var arr = []; for (var i = 0; i < n; i++) { arr.push(i); }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
Array constructor - 10 items
Array literal (assign by index) - 10 items
Fastest:
N/A
Slowest:
N/A
Latest run results:
No previous run results
This benchmark does not have any results yet. Be the first one
to run it!
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the benchmark and explain what's being tested. **Benchmark Overview** The benchmark measures the performance difference between two approaches to create an array in JavaScript: 1. **Using the `Array` constructor**: `var arr = new Array();` 2. **Using an array literal**: `var arr = [];` Both approaches are used with a loop that pushes elements to the array, where the number of iterations is specified by the variable `n`. **Options Compared** The two options being compared are: 1. Using the `Array` constructor: This approach creates an empty array and then dynamically adds elements to it using the `push()` method. 2. Using an array literal: This approach creates an array with no initial elements, and then pushes elements onto it using the `push()` method. **Pros and Cons of Each Approach** 1. **Using the `Array` constructor**: * Pros: Can be faster since the array is created upfront, reducing the number of dynamic allocations. * Cons: May lead to performance issues if the loop iterates a large number of times, as the array grows dynamically. 2. **Using an array literal**: * Pros: Typically more efficient for small arrays since it avoids dynamic allocation and allows for better cache locality. * Cons: Can be slower for very large arrays due to the overhead of creating an empty array with no initial elements. **Library Used** In this benchmark, none of the test cases use any external libraries. The code is self-contained, using only built-in JavaScript features. **Special JS Features or Syntax** There are no special JavaScript features or syntax being tested in this benchmark. The focus is on comparing two straightforward approaches to create an array. **Other Alternatives** If you were to modify the benchmark to test other approaches, some alternatives could be: 1. Using `Array.from()`: This method creates a new array from an iterable (e.g., an array literal or another array) and can be faster than using the `Array` constructor for large datasets. 2. Using `Array.prototype.concat()` or `Array.prototype.pushAll()`: These methods allow you to add multiple elements to an array, potentially reducing the number of iterations compared to pushing individual elements. The choice of alternative approaches would depend on the specific use case and performance characteristics being targeted.
Related benchmarks:
Maping BooleanArray vs uInt8 Array2 vs uint8 with bitMasking _2
constructor comparison vs. instanceof vs Array.isArray 2
Extending ArrayBufferView
subarray vs. constructor perf
new TypedArray() vs TypedArray.of()
Comments
Confirm delete:
Do you really want to delete benchmark?