rgrove

/*
The Express body-parser library, which you may be using to parse incoming JSON
request bodies, doesn't currently protect against prototype poisoning via the
`__proto__` key.

The dangers of prototype poisoning are described in detail here:
https://hueniverse.com/a-tale-of-prototype-poisoning-2610fa170061

Until body-parser provides its own fix, you can protect yourself by adding a
reviver function that throws an error if it sees any key named "__proto__". This

getify

function SomeCounter() {
    const [ counter, updateCounter ] = useState(0);
    
    useEffect(function listening(){
        const btn = document.getElementById("increment-counter-btn");
        btn.addEventListener("click",onClick);
    },[]);
    
    useEffect(function logger(){
        // this logger() is updated each time `counter` changes, so

rauschma

/* 
Proof of concept: Writing dual-mode (sync and async) code via generators

Recommendation: start by reading the example (at the end).

API:
– The API object is called `def`.
– Dual-mode `await`: const unwrapped = yield wrapped;
– Dual-mode `yield`: yield def.$one(singleValue)
– Dual-mode `yield*`: yield def.$all(iterable)

markmichon

class CircuitBreaker {
  constructor(request) {
    this.request = request
    this.state = "CLOSED"
    this.failureThreshold = 3
    this.failureCount = 0
    this.successThreshold = 2
    this.successCount = 0
    this.timeout = 6000
    this.nextAttempt = Date.now()

joelnet

// Y Combinator
const Y = a => (b => b (b)) (b => a (c => b (b) (c)))

// isomorphic Church encoding/decoding
const Church = {
  to: n => f => x => Array.from (Array (n)).reduce (f, x),
  from: f => f (x => x + 1) (0)
}

const True = a => b => a

john-doherty

(function () {

    'use strict';

    /**
     * wraps a promise in a timeout, allowing the promise to reject if not resolve with a specific period of time
     * @param {integer} ms - milliseconds to wait before rejecting promise if not resolved
     * @param {Promise} promise to monitor
     * @example
     *  promiseTimeout(1000, fetch('https://courseof.life/johndoherty.json'))

gragland

import { useState, useCallback } from "react";

function useToggle(initialValue = false){
  // State with initial boolean value (true/false)
  const [state, setState] = useState(initialValue);
  
  // Let's create a toggle function
  // This works, but we're using the state value from above
  // instead of the current state. Usually they are the same,
  // but if this hook was triggered multiple times rapidly then

Xavier577

Code snippet

import { createServer } from "http";
import crypto from "crypto";

const PORT = 8001;

// this is from the web-socket specification and not something that is generated
const WEBSOCKET_MAGIC_STRING_KEY = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";

guilhermesimoes

As soon as I saw the new YouTube Player and its new morphing play/pause button, I wanted to understand how it was made and replicate it myself.

From my analysis it looks like YouTube is using [SMIL animations][1]. I could not get those animations to work on browsers other than Chrome and it appears [that they are deprecated and will be removed][2]. I settled for the following technique:

1. Define the icon path elements inside a defs element so that they are not drawn.

2. Draw one icon by defining a use element whose xlink:href attribute points to one of the paths defined in the previous step. Simply [changing this attribute to point to the other icon is enough to swap them out][3], but this switch is not animated. To do that,

3. Replace the use with the actual path when the page is loaded.

shirakaba

Creating an Expo app in 2023

12th July, 2023. I'm going to try creating an iOS app called Paranovel, using Expo. My environment for mobile app dev (Xcode, Ruby, etc.) should be in reasonably good shape already as I frequently develop with React Native and NativeScript.

Creating the app

Go to https://docs.expo.dev, and see the Quick Start: npx create-expo-app paranovel

This runs with no problem, then I get this macOS system popup: