Provides a simple way to extract a list of unique domains from a HAR file (e.g. as downloadable from Chrome dev tools)

domainsFromHar.js

const fs = require('fs')
const urlLib = require('url')

function domainsFromHar(filePath) {
	const rawData = fs.readFileSync(filePath)
	const json = rawData && JSON.parse(rawData)
	const { log } = json || {}
	if (!log) return

	const { pages, entries } = log

	const urls = pages
		.map(page => page.title)
		.concat(entries.map(entry => entry.request.url))

	const domains = urls.map(url => urlLib.parse(url).host)

	const uniqueDomains = [...new Set(domains)]

	return JSON.stringify(uniqueDomains, null, 2)
}

const filePathArg = process.argv[2]
console.log(domainsFromHar(filePathArg))