Created
May 25, 2022 17:22
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CSS Coverage
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const puppeteer = require("puppeteer"); | |
// const crawlPage = require("./crawl-urls"); | |
const PAGE_URL = process.argv[2] || "https://pptr.dev"; | |
const bytesToSize = (bytes, decimals = 2) => { | |
if (bytes === 0) return "0 Bytes"; | |
const k = 1024; | |
const dm = decimals < 0 ? 0 : decimals; | |
const sizes = ["Bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"]; | |
const i = Math.floor(Math.log(bytes) / Math.log(k)); | |
return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + " " + sizes[i]; | |
}; | |
(async () => { | |
const browser = await puppeteer.launch(); | |
const page = await browser.newPage(); | |
// Gather coverage for CSS files | |
await Promise.all([page.coverage.startCSSCoverage()]); | |
await page.goto(PAGE_URL); | |
// Stops the coverage gathering | |
const [cssCoverage] = await Promise.all([page.coverage.stopCSSCoverage()]); | |
// Calculates # bytes being used based on the coverage | |
const calculateUsedBytes = (type, coverage) => | |
coverage.map(({ url, ranges, text }) => { | |
let usedBytes = 0; | |
ranges.forEach((range) => (usedBytes += range.end - range.start - 1)); | |
return { | |
url, | |
type, | |
usedBytes, | |
totalBytes: text.length, | |
percentUsed: `${((usedBytes / text.length) * 100).toFixed(2)}%`, | |
}; | |
}); | |
const calculateUsedBytesCssCoverage = [ | |
...calculateUsedBytes("css", cssCoverage), | |
]; | |
// calculateUsedBytesCssCoverage.map((cssResource) => { | |
// if (cssResource.usedBytes === 0) console.log(cssResource); | |
// }); | |
const unusedCssResources = calculateUsedBytesCssCoverage.filter( | |
(cssResource) => cssResource.usedBytes === 0 | |
); | |
const totalUnusedBytes = unusedCssResources | |
.map((cssResource) => cssResource.totalBytes) | |
.reduce((acc, cur) => acc + cur, 0); | |
console.log(unusedCssResources); | |
console.log("Total Unused CSS:", bytesToSize(totalUnusedBytes)); | |
await browser.close(); | |
})(); |
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{ | |
"name": "webperf-puppeteer", | |
"version": "1.0.0", | |
"description": "Web Performance Puppeteer Scripts", | |
"main": "index.js", | |
"scripts": { | |
"test": "node ./css-coverage.js https://joanleon.dev" | |
}, | |
"keywords": [ | |
"webperf", | |
"performacne", | |
"puppeteer", | |
"wpo" | |
], | |
"author": "Joan Leon | @nucliweb", | |
"license": "MIT", | |
"dependencies": { | |
"puppeteer": "^9.1.1" | |
} | |
} |
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