Files
bsky-social-app/scripts/measure-web-bundle.js
2026-09-07 13:57:56 +02:00

131 lines
4.2 KiB
JavaScript

/*
* Measures the initial payload of the exported web bundle.
*
* Reads index.html from the export directory, collects every local resource
* referenced by <script src> / <link href> tags, sums their sizes plus the
* size of index.html itself, and prints the total in bytes to stdout.
* Per-file details go to stderr, so callers can do:
*
* SIZE=$(node scripts/measure-web-bundle.js --exclude '\.ico$|\.woff2?$')
*
* Lazily-loaded chunks (locale messages, hls, etc.) are not referenced from
* index.html and therefore do not count toward the total.
*
* The export directory is auto-detected: Metro exports to dist/, the old
* webpack config exported to web-build/. This lets CI compare a Metro-built
* PR against a webpack-built base commit with the same command; pass --dir
* to override.
*/
const fs = require('node:fs')
const path = require('node:path')
const projectRoot = path.join(__dirname, '..')
function usage() {
console.error(
'Usage: node scripts/measure-web-bundle.js [--dir <path>] [--exclude <regex>]... [--allow-missing]',
)
process.exit(1)
}
let dirArg = null
let allowMissing = false
const excludes = []
const argv = process.argv.slice(2)
for (let i = 0; i < argv.length; i++) {
if (argv[i] === '--dir' && argv[i + 1]) {
dirArg = argv[++i]
} else if (argv[i] === '--exclude' && argv[i + 1]) {
excludes.push(argv[++i])
} else if (argv[i] === '--allow-missing') {
allowMissing = true
} else {
usage()
}
}
const candidates = dirArg
? [path.resolve(dirArg)]
: [path.join(projectRoot, 'dist'), path.join(projectRoot, 'web-build')]
const outDir = candidates.find(dir => fs.existsSync(dir))
if (!outDir) {
console.error(
`Web build output not found (looked for ${candidates.join(', ')}). ` +
'Run pnpm build-web first.',
)
process.exit(1)
}
const indexPath = path.join(outDir, 'index.html')
if (!fs.existsSync(indexPath)) {
console.error(`${indexPath} not found. Run pnpm build-web first.`)
process.exit(1)
}
const excludeRes = excludes.map(pattern => new RegExp(pattern))
const html = fs.readFileSync(indexPath, 'utf8')
/*
* Every fetched-on-load resource is referenced via a src/href attribute on a
* <script> or <link> tag. Inline url(...) references (e.g. the italic font in
* the splash CSS) are fetched on demand, so they are intentionally skipped.
*/
const urls = new Set()
for (const match of html.matchAll(
/<(?:script|link)\b[^>]*?\b(?:src|href)="([^"]+)"/g,
)) {
urls.add(match[1])
}
/*
* URLs are root-relative as served in production, where the export lives
* under the app.config.js baseUrl ('/static'). On disk both '/static/foo'
* and '/foo' resolve to '<outDir>/foo', so try the path with and without
* the baseUrl prefix.
*/
function resolveLocal(url) {
const rel = url.replace(/^\//, '')
for (const candidate of [rel, rel.replace(/^static\//, '')]) {
const abs = path.join(outDir, candidate)
if (fs.existsSync(abs)) return {rel: candidate, abs}
}
return null
}
let total = fs.statSync(indexPath).size
let count = 1
console.error(`${String(total).padStart(12)} index.html`)
for (const url of [...urls].sort()) {
if (/^(?:https?:)?\/\//.test(url) || url.startsWith('data:')) continue
const resolved = resolveLocal(url)
if (!resolved) {
/*
* By default fail loudly: a missing referenced asset means the layout
* changed and the measurement would silently undercount. --allow-missing
* downgrades this to a warning for outputs that intentionally reference
* resources served from elsewhere.
*/
console.error(`Referenced resource not found in ${outDir}: ${url}`)
if (!allowMissing) process.exit(1)
continue
}
if (excludeRes.some(re => re.test(resolved.rel))) continue
const {size} = fs.statSync(resolved.abs)
total += size
count++
console.error(`${String(size).padStart(12)} ${resolved.rel}`)
}
if (count === 1) {
// Fail loudly: index.html referencing no assets means the build output
// layout changed and a near-0 measurement would corrupt the CI size diff.
console.error(`No resources measured from ${indexPath}; check the build.`)
if (!allowMissing) process.exit(1)
}
console.error(
`Measured index.html + ${count - 1} referenced assets in ${outDir}: ${(total / 1024).toFixed(2)} KB`,
)
console.log(total)