read-mode.js

// require https://raw.githubusercontent.com/mozilla/readability/master/Readability.js

function uri(x) {
	const a = document.createElement('a')
	a.href = x
	const {href, hostname, pathname, protocol} = a
	return {
		spec: href, host: hostname,
		prePath: protocol + '//' + hostname,
		scheme: protocol.substr(0, protocol.indexOf(':')),
		pathBase: protocol + '//' + hostname + pathname.substr(0, pathname.lastIndexOf('/') + 1)
	}
}

async function doc(x) {
	if(window.location.href === x) return new DOMParser().parseFromString(window.document.documentElement.outerHTML, 'text/html')

	const response = await fetch(x)
	const contentType = response.headers.get("content-type")

	let ct = 'text/html'
	if(!(
		response.ok && contentType && (
			contentType.includes("text/html") && ((ct = 'text/html'), true) ||
			contentType.includes("application/xhtml") && ((ct = 'application/xhtml'), true) ||
			contentType.includes("application/xml") && ((ct = 'application/xml'), true)
		)
	)) throw new TypeError("wat")

	return new DOMParser().parseFromString(await response.text(), ct)
}

async function read(x) {
	const d = await doc(x)
	return new Readability(uri(x), d).parse()
}