var arr = Array.from({length: 1000});
var arr2 = [];
for (let i = 0; i < arr.length; i++){
arr2.unshift(arr[i]);
}
var arr3 = [arr].reverse();
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
unshift | |
push + reverse |
Test name | Executions per second |
---|---|
unshift | 4566.1 Ops/sec |
push + reverse | 168133.8 Ops/sec |
Let's break down the provided benchmark and explain what's being tested, compared, and analyzed.
Benchmark Definition
The benchmark definition consists of two test cases: unshift
and push + reverse
. The tests are designed to measure the performance difference between using the unshift()
method versus a combination of push()
and reverse()
methods on an array.
Test Case 1: unshift
for (let i = 0; i < arr.length; i++) { arr2.unshift(arr[i]); }
unshift()
method to add elements to the beginning of an array.unshift()
method's performance in a loop, which is common in many JavaScript applications.Test Case 2: push + reverse
var arr3 = [...arr].reverse();
push()
method to add elements to the end of an array and then reversing the array.reverse()
method, which is commonly used for array reversal.Library: Array.from()
In the benchmark definition, Array.from()
is used to create a new array with a specified length. This method is designed to mimic the behavior of older browsers that don't support the modern Array.prototype.fill()
method.
Special JS feature: Spread operator (...
)
In the benchmark definition, the spread operator is used to create a new array by spreading the contents of arr
. This syntax was introduced in ECMAScript 2015 (ES6) and has since become widely supported.
Alternatives
Other alternatives for testing array insertion performance could include:
Array.prototype.fill()
instead of unshift()
.splice()
method, which allows you to insert elements at specific indices.The provided benchmark is well-designed and covers common scenarios for testing array insertion performance. However, it's essential to note that the results may not be representative of all use cases, and additional tests might be necessary to ensure comprehensive coverage.