Run results for: querySelector vs querySelector + cache using Map2

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser: Chrome 83

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
querySelector	657721.9 Ops/sec
querySelector + cache with Map	5329.6 Ops/sec

HTML Preparation code:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1 class="about-shop">Hello azula</h1>
</body>
</html>

Script Preparation code:

const cache = new Map();

    function $(selector) {
        if (cache.has(selector)) {
            return cache.get(selector);
        }

        let cached = document.querySelector(selector);
        cache.set(selector, cached);
        return cached
    };

Tests:

querySelector
const selector1 = document.querySelector(".about-shop"); const selector2 = document.querySelector(".about-shop"); const selector3 = document.querySelector(".about-shop");
querySelector + cache with Map
const selector1 = $(".about-shop"); const selector2 = $(".about-shop"); const selector3 = $(".about-shop");

Run results for: querySelector vs querySelector + cache using Map2

querySelector

querySelector + cache with Map