David Andersson lejonmanen

lejonmanen / better.js

Last active October 24, 2024 15:32

Using Node.js async readline

	import readline from 'node:readline'

	async function ask(query) {
	const rl = readline.createInterface({ input: process.stdin, output: process.stdout, tabSize: 4 });

	return new Promise((resolve) => rl.question(query, (answer) => {
	rl.close();
	resolve(answer);
	}));
	}

lejonmanen / ContextDemo.jsx

Created April 11, 2022 09:43

React Context demo using hooks

	import { createContext, useState, useContext } from 'react'


	// Create the context in a separate file. Import it to every component that needs it.
	const CounterContext = createContext(0)


	const ContextDemo = () => {
	const [count, setCount] = useState(2)
	const contextValue = { count, setCount }

lejonmanen / MediaDevice.jsx

Created November 11, 2021 20:40

Use MediaDevices to display video stream from webcam in a React component.

	import { useRef } from 'react'

	const MediaDevice = () => {
	const videoRef = useRef(null)

	const handleVideoOn = () => assignStream(videoRef.current)
	const handleVideoOff = () => videoRef.current.srcObject = null

	return (
	<div>

lejonmanen / useCancellableAjax.js

Last active March 20, 2024 21:47

React hook for sending fetch requests and cancelling them safely.

	import { useEffect, useRef } from 'react'

	/*
	Safely send and cancel one AJAX request at the time. If you need to send multiple requests at the same time, call this hook several times.

	Usage:
	const [cancelRef, doAjax] = useCancellableAjax()

	Fetch data. Tip: use a setState function as callback.
	doAjax(url, fetchOptions, dataCallback)

lejonmanen / script.js

Last active December 20, 2021 15:46

Minimal service worker for use when developing a PWA

	// Copy and paste this code into your main script file
	// The purpose is to register the service worker
	// The browser will load sw.js for us if you do this

	if ('serviceWorker' in navigator) {
	// Assumes your service worker has file name "sw.js"
	navigator.serviceWorker.register('sw.js')
	.then(reg => {
	console.log('Registration succeeded. Scope is ' + reg.scope);
	});