var n = 10;
var arr = new Array();
for (var i = 0; i < n; i++) {
arr.push(i);
}
var n = 10;
var arr = [];
for (var i = 0; i < n; i++) {
arr.push(i);
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Array constructor - 10 items | |
Array literal (assign by index) - 10 items |
Test name | Executions per second |
---|---|
Array constructor - 10 items | 4695157.5 Ops/sec |
Array literal (assign by index) - 10 items | 26121056.0 Ops/sec |
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:
Array
constructor: var arr = new Array();
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:
Array
constructor: This approach creates an empty array and then dynamically adds elements to it using the push()
method.push()
method.Pros and Cons of Each Approach
Array
constructor: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:
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.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.