<div class='lazyload'></div>
var e = document.querySelector(".lazyload");
if (e.className === "lazyload") {
e.classList.remove("lazyload");
e.classList.add("lazyloading");
}
if (e.className === "lazyload") {
e.className = e.className.replace(
"lazyload",
"lazyloading"
);
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Case 1 | |
Case 2 |
Test name | Executions per second |
---|---|
Case 1 | 10215353.0 Ops/sec |
Case 2 | 10285225.0 Ops/sec |
I'll break down the benchmark and explain what's being tested, compared, and their pros/cons.
Benchmark Overview
The benchmark tests two different approaches to remove the lazyload
class from an HTML element and replace it with lazyloading
. The test cases are represented by the JSON data provided.
Script Preparation Code
The script preparation code is:
var e = document.querySelector(".lazyload");
This line of code selects an HTML element with the class lazyload
using the document.querySelector()
method. This line is executed before each test case.
Html Preparation Code
The html preparation code is:
<div class='lazyload'></div>
This line of code creates a new HTML element with the class lazyload
. This element will be modified by the test cases.
Test Cases
There are two test cases:
if (e.className === "lazyload") {
e.classList.remove("lazyload");
e.classList.add("lazyloading");
}
This test case uses a direct property access to check if the className
property of the element is equal to "lazyload"
. If true, it removes the lazyload
class and adds the lazyloading
class.
if (e.className === "lazyload") {
e.className = e.className.replace("lazyload", "lazyloading");
}
This test case uses a regular expression to replace "lazyload"
with "lazyloading"
in the className
property of the element. If the element's class name starts with "lazyload"
, it will be replaced with "lazyloading"
.
Comparison
The two test cases are compared to see which approach is faster. The benchmark measures the number of executions per second for each test case.
Pros and Cons:
Pros:
Cons:
className
property is empty or contains only whitespacePros:
className
property is empty or contains only whitespaceCons:
Other Considerations
className
property. In some cases, this might lead to unexpected behavior or even vulnerabilities.Library/Functionality Used
The test cases use the following JavaScript functionality:
document.querySelector()
(a method of the Document
object)e.classList.remove()
e.classList.add()
replace()
method)These functions are part of the standard JavaScript API and don't require any external libraries.
Special JS Feature/Syntax
This benchmark doesn't use any special JavaScript features or syntax. However, it does rely on modern browser support for classes as properties (introduced in ECMAScript 2015).
Alternatives
If you want to test alternative approaches, you could consider the following: