kennetpostigo

First couple things I thought about when migrating after reading the docs

So migrating my existing app wasn't as troublesome as I originally thought. First thing I did was take a look at my router and routes and figure try to make a mental model of all the files where I had nested routes in the existing app because those components/containers will contain {this.props.children}. So I need to replace those with the nested <Match /> components.

So just to give an example:

In v2:

<Router history={history}>
  <Route path="/" component={App}>

acdlite

// getComponent is a function that returns a promise for a component
// It will not be called until the first mount
function asyncComponent(getComponent) {
  return class AsyncComponent extends React.Component {
    static Component = null;
    state = { Component: AsyncComponent.Component };

    componentWillMount() {
      if (!this.state.Component) {
        getComponent().then(Component => {

Rich-Harris

Edit — February 2019

This gist had a far larger impact than I imagined it would, and apparently people are still finding it, so a quick update:

• TC39 is currently moving forward with a slightly different version of TLA, referred to as 'variant B', in which a module with TLA doesn't block sibling execution. This vastly reduces the danger of parallelizable work happening in serial and thereby delaying startup, which was the concern that motivated me to write this gist
• In the wild, we're seeing (async main(){...}()) as a substitute for TLA. This completely eliminates the blocking problem (yay!) but it's less powerful, and harder to statically analyse (boo). In other words the lack of TLA is causing real problems
• Therefore, a version of TLA that solves the original issue is a valuable addition to the language, and I'm in full support of the current proposal, which you can read here.

I'll leave the rest of this document unedited, for archaeological

iammerrick

import React from 'react';

const toPromise = (load) => (new Promise((resolve) => (
  load(resolve)
)));

class LazilyLoad extends React.Component {

  constructor() {
    super(...arguments);

garybernhardt

This document has moved!

It's now here, in The Programmer's Compendium. The content is the same as before, but being part of the compendium means that it's actively maintained.

ryanflorence

Performance and Conditionally Rendered Content in React

First, this is not about if in JSX. It's just the simplest example to talk about (and a lot of people tried to do it at first a long time ago).

Some react components conditionally render content. When React first went public, a lot of us coming from handlebars really wanted "if" syntax. This gist isn't just about If components though, it's about

Rich-Harris

Stuff I wish I'd known sooner about service workers

I recently had several days of extremely frustrating experiences with service workers. Here are a few things I've since learned which would have made my life much easier but which isn't particularly obvious from most of the blog posts and videos I've seen.

I'll add to this list over time – suggested additions welcome in the comments or via twitter.com/rich_harris.

Use Canary for development instead of Chrome stable

Chrome 51 has some pretty wild behaviour related to console.log in service workers. Canary doesn't, and it has a load of really good service worker related stuff in devtools.

JamieMason

Quick way to generate a table of contents from a GitHub README

Visit the README.md on GitHub.

Paste this into the console in Google Chrome.

[].map
  .call(document.querySelectorAll('.anchor'), el => 
 `* [${el.parentNode.innerText}](${el.getAttribute('href')})`

kosamari

ServiceWorker for github pages

This is a ServiceWorker template to turn small github pages into offline ready app.

Why ?

Whenever I make small tools & toys, I create github repo and make a demo page using github pages (like this one).
Often these "apps" are just an index.html file with all the nessesary CSS and JavaScript in it (or maybe 2-3 html/css/js files). I wanted to cache these files so that I can access my tools offline as well.

Notes

Make sure your github pages have HTTPS enforced, you can check Settings > GitHub Pages > Enforce HTTPS of your repository.

ryanflorence

if (
  process.env.NODE_ENV === 'production' &&
  window.__REACT_DEVTOOLS_GLOBAL_HOOK__ &&
  Object.keys(window.__REACT_DEVTOOLS_GLOBAL_HOOK__._renderers).length
) {
  window.__REACT_DEVTOOLS_GLOBAL_HOOK__._renderers = {}
}