eps1lon

Summary explainer: facebook/react#20031 (comment)

playground:

Input:

<ComponentA />;
<ComponentD prop="A" key="K" />;
<ComponentB {...props} />;
;

sindresorhus

Pure ESM package

The package that linked you here is now pure ESM. It cannot be require()'d from CommonJS.

This means you have the following choices:

1. Use ESM yourself. (preferred)
   Use import foo from 'foo' instead of const foo = require('foo') to import the package. You also need to put "type": "module" in your package.json and more. Follow the below guide.
2. If the package is used in an async context, you could use await import(…) from CommonJS instead of require(…).
3. Stay on the existing version of the package until you can move to ESM.

tannerlinsley

Replacing Create React App with the Next.js CLI

How dare you make a jab at Create React App!?

Firstly, Create React App is good. But it's a very rigid CLI, primarily designed for projects that require very little to no configuration. This makes it great for beginners and simple projects but unfortunately, this means that it's pretty non-extensible. Despite the involvement from big names and a ton of great devs, it has left me wanting a much better developer experience with a lot more polish when it comes to hot reloading, babel configuration, webpack configuration, etc. It's definitely simple and good, but not amazing.

Now, compare that experience to Next.js which for starters has a much larger team behind it provided by a world-class company (Vercel) who are all financially dedicated to making it the best DX you could imagine to build any React application. Next.js is the 💣-diggity. It has amazing docs, great support, can grow with your requirements into SSR or static site generation, etc.

So why

RyanCavanaugh

Strict Environment

Problem Statement

Strict Environment is intended to address three distinct problems that are frequently encountered by TypeScript developers.

This is an alternative approach to solving the problems that placeholder types were intended to address.

Problem 1: Augmentation Pollution

threepointone

(I'm enjoying doing these raw, barely edited writeups; I hope they're useful to you too)

Feature flags

This is my own writeup on feature flags; for a deep dive I'd recommend something like Martin Fowler's article (https://martinfowler.com/articles/feature-toggles.html).

So. Feature flags. The basic idea that you'll store configuration/values on a database/service somewhere, and by changing those values, you can change the user experience/features for a user on the fly.

Let's say that you're building a new feature, called 'new-button' which changes the color of buttons, which is currently red, to blue. Then you'd change code that looks like this -

sibelius

import MomentUtils from '@date-io/moment';

class MomentUTCUtils extends MomentUtils {
  format(value, formatString) {
    return this.moment.utc(value).format(formatString);
  }

  parse(value: string, format: string) {
    if (value === '') {
      return null;

ryanflorence

Everything I Know About UI Routing

Definitions

1. Location - The location of the application. Usually just a URL, but the location can contain multiple pieces of information that can be used by an app
   1. pathname - The "file/directory" portion of the URL, like invoices/123
   2. search - The stuff after ? in a URL like /assignments?showGrades=1.
   3. query - A parsed version of search, usually an object but not a standard browser feature.
   4. hash - The # portion of the URL. This is not available to servers in request.url so its client only. By default it means which part of the page the user should be scrolled to, but developers use it for various things.
   5. state - Object associated with a location. Think of it like a hidden URL query. It's state you want to keep with a specific location, but you don't want it to be visible in the URL.

threepointone

https://twitter.com/snookca/status/1073299331262889984?s=21

‪“‬In what way is JS any more maintainable than CSS? How does writing CSS in JS make it any more maintainable?”

‪Happy to chat about this. There’s an obvious disclaimer that there’s a cost to css-in-js solutions, but that cost is paid specifically for the benefits it brings; as such it’s useful for some usecases, and not meant as a replacement for all workflows. ‬

‪(These conversations always get heated on twitter, so please believe that I’m here to converse, not to convince. In return, I promise to listen to you too and change my opinions; I’ve had mad respect for you for years and would consider your feedback a gift. Also, some of the stuff I’m writing might seem obvious to you; I’m not trying to tell you if all people of some of the details, but it might be useful to someone else who bumps into this who doesn’t have context)‬

So the big deal about css-in-js (cij) is selectors.

yelouafi

<!doctype html>
<html lang="en">
  <body>
<script>

const sagaMiddleware = store => gen => {
  
  var resolve, reject
  var done = new Promise((res, rej) => {
    resolve = res

gaearon

// connect() is a function that injects Redux-related props into your component.
// You can inject data and callbacks that change that data by dispatching actions.
function connect(mapStateToProps, mapDispatchToProps) {
  // It lets us inject component as the last step so people can use it as a decorator.
  // Generally you don't need to worry about it.
  return function (WrappedComponent) {
    // It returns a component
    return class extends React.Component {
      render() {
        return (