var arr = Array.from({length: 100000}).map((_, i) => ({i}));
var arr2 = [];
for (let i = 0; i < arr.length; i++){
arr2.unshift({arr[i]});
}
var arr3 = arr.map(o=>({o})).reverse();
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
unshift | |
reverse |
Test name | Executions per second |
---|---|
unshift | 0.4 Ops/sec |
reverse | 260.0 Ops/sec |
Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.
Benchmark Overview
The benchmark is designed to measure the performance difference between two approaches: using unshift()
and reversing an array by creating a new reversed copy. The test case consists of a small JavaScript array with 100,000 elements, which is first cloned into a new variable arr2
using unshift()
. Another test case measures the execution time of reversing the original array arr
using the map()
and reverse()
methods.
Library Usage
There is no explicit library usage in this benchmark. However, it's worth noting that the Array.from()
method used to create the initial array is a part of the ECMAScript standard, which means it's not specific to any particular library or framework.
Special JavaScript Features/Syntax
The test cases use the following special features/syntax:
{...arr[i]}
) and the unshift()
method, which are both relatively modern features introduced in ECMAScript 2015 (ES6).map()
method, which is also a feature introduced in ES6.Approach Comparison
There are two approaches being compared:
unshift()
: This approach creates a new array and appends the elements to it using unshift()
, while preserving the original order of elements. The benchmark measures how long this process takes.map()
method to create a new copy of each element in the original array, and then reverses the resulting array using the reverse()
method. The benchmark measures how long this process takes.Pros/Cons of Each Approach
Using unshift()
:
Pros:
Cons:
Reversing by creating a new reversed copy:
Pros:
Cons:
Other Considerations
When choosing between these approaches, consider the following factors:
unshift()
with a large array can lead to increased garbage collection overhead and slower performance.unshift()
might be the better option.Alternatives
Other alternatives to these approaches include:
splice()
to insert or remove elements from an arrayinsertAt()
, map
and reverse
functions for more complex data manipulation tasksuseReducer
hook or Vue's ref
system.Keep in mind that the best approach will depend on your specific use case and requirements.