staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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gaearon

function mapValues(obj, fn) {
  return Object.keys(obj).reduce((result, key) => {
    result[key] = fn(obj[key], key);
    return result;
  }, {});
}

function pick(obj, fn) {
  return Object.keys(obj).reduce((result, key) => {
    if (fn(obj[key])) {

bradwestfall

S3 Static Sites

⚠ This post is fairly old. I don't keep it up to date. Be sure to see comments where some people have posted updates

What this will cover

• Host a static website at S3
• Redirect www.website.com to website.com
• Website can be an SPA (requiring all requests to return index.html)
• Free AWS SSL certs
• Deployment with CDN invalidation

EvanBacon

Many ways to useHooks

When I try to learn something, I search around for the optimal approach. In the case of hooks I found two reasonable approaches and one approach that only makes sense in some use-cases. Below I've documented all of them.

Use Case (useCase 😘)

I want to change the style of a text element when the user is clicking down on it. Because this is React Native for web, there are no CSS pseudo classes, so I need to manage all of the state myself. Because classes like active, focus, hover, and visited could be commonly used the API must be very self-contained. ... and I want people to like me, so I'm using hooks (the old implementation used render props).

Spread props

jrom

    if ($request_uri = /) { 
      set $test  A; 
    } 
  
    if ($host ~* teambox.com) { 
      set $test  "${test}B"; 
    } 
  
    if ($http_cookie !~* "auth_token") { 
      set $test  "${test}C"; 

ryanflorence

Folder Structure

Please note

While this gist has been shared and followed for years, I regret not giving more background. It was originally a gist for the engineering org I was in, not a "general suggestion" for any React app.

Typically I avoid folders altogether. Heck, I even avoid new files. If I can build an app with one 2000 line file I will. New files and folders are a pain.

max-mapper

JavaScript function hoisting by example

Below are many examples of function hoisting behavior in JavaScript. Ones marked as works successfuly print 'hi!' without errors.

To play around with these examples (recommended) clone them with git and execute them with e.g. node a.js

Notes on hoisting

(I may be using incorrect terms below, please forgive me)

sebmarkbage

import { Component } from "React";

export var Enhance = ComposedComponent => class extends Component {
  constructor() {
    this.state = { data: null };
  }
  componentDidMount() {
    this.setState({ data: 'Hello' });
  }
  render() {

martinsik

$(function () {
    "use strict";

    // for better performance - to avoid searching in DOM
    var content = $('#content');
    var input = $('#input');
    var status = $('#status');

    // my color assigned by the server
    var myColor = false;

pbojinov

Two way iframe communication

The main difference between the two pages is the method of sending messages. Recieving messages is the same in both.

Parent

Send messages to iframe using iframeEl.contentWindow.postMessage Recieve messages using window.addEventListener('message')

iframe