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@jridgewell
Last active August 5, 2020 21:39
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Adopted vs legacy stylesheets (https://jsbench.github.io/#0bd7efc7c75ef828464d8428c3535a67) #jsbench #jsperf
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>Adopted vs legacy stylesheets</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/benchmark/1.0.0/benchmark.min.js"></script>
<script src="./suite.js"></script>
</head>
<body>
<h1>Open the console to view the results</h1>
<h2><code>cmd + alt + j</code> or <code>ctrl + alt + j</code></h2>
</body>
</html>
"use strict";
(function (factory) {
if (typeof Benchmark !== "undefined") {
factory(Benchmark);
} else {
factory(require("benchmark"));
}
})(function (Benchmark) {
var suite = new Benchmark.Suite;
Benchmark.prototype.setup = function () {
var container = document.createElement('div');
document.body.appendChild(container);
var host = document.createElement('div');
container.appendChild(host);
var shadowRoot = host.attachShadow({mode: 'open'});
var CSS = '.class1 {background: red; width: 100px; height: 100px}';
function uniqueCss() {
return CSS.replace('red', 'rgba(' +
(Math.floor(Math.random() * 255)) +
',' +
(Math.floor(Math.random() * 255)) +
',' +
(Math.floor(Math.random() * 255)) +
')');
}
if (!window.cachedStyleSheet) {
window.cachedStyleSheet = new CSSStyleSheet();
window.cachedStyleSheet.replaceSync(CSS);
window.cachedBlobUrl = URL.createObjectURL(new Blob([CSS], { type: 'text/css' }));
}
function addContent() {
var content = document.createElement('div');
content.className = 'class1';
shadowRoot.appendChild(content);
// var bg = getComputedStyle(content).backgroundColor;
// if (bg !== 'rgb(255, 0, 0)' && bg !== 'red') {
// throw new Error('not red');
// }
}
};
Benchmark.prototype.teardown = function () {
container.textContent = '';
};
suite.add("Legacy stylesheet", function () {
// Legacy stylesheet
var style = document.createElement('style');
style.textContent = uniqueCss();
shadowRoot.appendChild(style);
addContent();
});
suite.add("Recreated adopted", function () {
// Recreated adopted
var styleSheet = new CSSStyleSheet();
styleSheet.replaceSync(uniqueCss());
shadowRoot.adoptedStyleSheets = [styleSheet];
addContent();
});
suite.add("Cached adopted", function () {
// Cached adopted
shadowRoot.adoptedStyleSheets = [window.cachedStyleSheet];
addContent();
});
suite.add("Cached blob", function () {
// Cached blob
var link = document.createElement('link');
link.rel = 'stylesheet';
link.href = window.cachedBlobUrl;
shadowRoot.appendChild(link);
addContent();
});
suite.on("cycle", function (evt) {
console.log(" - " + evt.target);
});
suite.on("complete", function (evt) {
console.log(new Array(30).join("-"));
var results = evt.currentTarget.sort(function (a, b) {
return b.hz - a.hz;
});
results.forEach(function (item) {
console.log((idx + 1) + ". " + item);
});
});
console.log("Adopted vs legacy stylesheets");
console.log(new Array(30).join("-"));
suite.run();
});
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