Katarn

This is just a dump of some interesting undocumented features of webOS (3.8 specifically, on early 2018 4k LG TV) and other development-related tips.

Homebrew app ideas

OpenVPN frontend (OpenVPN itself is easily buildable and runs on webOS TVs: https://discord.com/channels/407937994037919756/835489130967859251/906943542457401395)
App autostart manager - dynamically update arbitrary app config and register it as input (see Registering an app as an input)
webos-vncserver frontend with autostart option
Package hyperiond into Piccap directly
Quick Screenshot (expose HTTP port that just returns PNG of current screen contents)
Custom IR remote codes editor/updater/blaster

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

	import { writable } from 'svelte/store'

	// returns a store with HTTP access functions for get, post, patch, delete
	// anytime an HTTP request is made, the store is updated and all subscribers are notified.
	export default function(initial) {
	// create the underlying store
	const store = writable(initial)

	// define a request function that will do `fetch` and update store when request finishes
	store.request = async (method, url, params=null) => {

	import httplib
	import socket
	import StringIO

	# generic
	SSDP_ALL = 'ssdp:all'
	UPNP_ROOT = 'upnp:rootdevice'

	# devices
	DIAL = 'urn:dial-multiscreen-org:service:dial:1'

	# Клонируем исходный репозиторий без рабочего каталога (--bare)
	git clone --bare https://github.com/exampleuser/old-repository.git


	cd old-repository.git
	# Делаем mirror-push(будут скопированы все ветки и тэги) в новый репозиторий
	git push --mirror https://github.com/exampleuser/new-repository.git

	cd ..
	# Удаляем папку с репозиторием

	// ==UserScript==
	// @name LinkDragSelectionForChrome
	// @description Opera like link selection for chrome.
	// @namespace http://d.hatena.ne.jp/Griever/
	// @author Griever
	// @license MIT License
	// @match http:///
	// @match https:///
	// @version 0.0.1
	// ==/UserScript==

	var net = require('net');
	var fs = require('fs');

	// file name for the current log
	var fileName = __dirname + '/log_' + new Date().getTime();

	// Start a TCP Server
	var server = net.createServer(function (socket) {

	// Log what the TV sends