CLI that gets remote sizes of repositories; human-readable

gh-repo-size

#!/usr/bin/env node
//@ts-check
import assert from 'node:assert/strict'
import { argv } from 'node:process'

for (const arg of argv.slice(2)) {
	// UX
	const user_repo = (() => {
		const a = arg.trim()
		return a.slice(
			+(a[0] == '/'),
			//@ts-expect-error 2550
			a.at(-1) == '/' ? -1 : undefined
		)
	})()

	// regex is permissive, to be future-proof
	if (!/^[^\x00-\x0a/\s]+\/[^\x00-\x0a/\s]+$/.test(user_repo)) {
		console.error(`${user_repo} malformed`)
		continue
	}

	const r = await fetch('https://api.github.com/repos/' + user_repo)
	if (!r.ok) {
		console.error(`${user_repo} ${r.status} ${r.statusText}`)
		continue
	}
	// full `JSON.parse` is overkill (bad perf),
	// but it's guaranteed to be reliable
	const kilobytes = (await r.json()).size

	assert(
		// allow TS to narrow the `any`
		typeof kilobytes == 'number' &&
		// in theory, a number-literal can parse as `Infinity`!
		// in practice, that'll never happen... right? 👀😅
		isFinite(kilobytes),
		'API broken'
	)

	// 1024 is for kibibytes
	const bytes = kilobytes * 1e3
	assert(Number.isInteger(bytes))

	// floor (`toUint32`) logarithm base 1000
	const i = Math.log10(bytes) / 3 >>> 0

	// https://en.wikipedia.org/wiki/Binary_prefix
	// 1QB ≅ 2^99B,
	// therefore the OOB index is practically impossible
	console.log(`${user_repo} ${(bytes / 1e3 ** i).toFixed(1)} ${'KMGTPEZYRQ'[i - 1] || ''}B`)
}